WO2019093369A1

WO2019093369A1 - Iridium complex compound, composition containing said compound and solvent, organic electroluminescent element containing said compound, display device, and illumination device

Info

Publication number: WO2019093369A1
Application number: PCT/JP2018/041327
Authority: WO
Inventors: 和弘長山; 王己家村
Original assignee: 三菱ケミカル株式会社
Priority date: 2017-11-07
Filing date: 2018-11-07
Publication date: 2019-05-16
Also published as: JP7439891B2; CN111263766B; CN116655702A; CN111263766A; EP3708571A1; KR20200078499A; JP2023036713A; KR20230173735A; JP7238782B2; US20200317706A1; EP3708571A4; JPWO2019093369A1

Abstract

An iridium complex compound represented by formula (1). [In the formula: Ir represents an iridium atom; C1-C6 represent carbon atoms; N1 and N2 represent nitrogen atoms; R1-R4 represent hydrogen atoms or substituents; a-d are each integer maximum numbers of rings Cy1-Cy4 that can be substituted; m and n are 1 or 2, where m + n = 3; the ring Cy1 is represented by formula (2) or (2'); ring Cy3 is an aromatic ring or a heteroaromatic ring including carbon atoms C4 and C5; and ring Cy4 Cy4 is a heteroaromatic ring including a carbon atom C6 and a nitrogen atom N2.]

Description

Iridium complex compound, composition containing the compound and solvent, organic electroluminescent device containing the compound, display device and lighting device

The present invention relates to an iridium complex compound, and more particularly to an iridium complex compound useful as a material of a light emitting layer of an organic electroluminescent device (hereinafter sometimes referred to as “organic EL device”). The present invention also relates to a composition containing the compound and a solvent, an organic electroluminescent device containing the compound, and a display device and a lighting device having the organic electroluminescent device.

Various electronic devices using organic EL elements, such as organic EL lighting and organic EL display, have been put to practical use. Organic electroluminescent devices have low applied voltage and low power consumption and can emit light of three primary colors, so applications to medium- and small-sized displays represented by mobile phones and smartphones as well as large display monitors are beginning. .

An organic electroluminescent element is manufactured by laminating | stacking several layers, such as a light emitting layer, a charge injection layer, and a charge transport layer. At present, many organic electroluminescent devices are manufactured by vapor-depositing an organic material under vacuum, but in the vacuum vapor deposition method, the vapor deposition process becomes complicated and the productivity is poor. In the organic electroluminescent element manufactured by the vacuum evaporation method, it is extremely difficult to increase the size of the illumination or display panel.

In recent years, a wet film formation method (coating method) has been studied as a process for efficiently manufacturing an organic electroluminescent device that can be used for a large display or illumination. The wet film formation method has an advantage of being able to easily form a stable layer as compared with the vacuum deposition method, and therefore, it is expected to be applied to mass production of displays and lighting devices and to large devices.

In order to manufacture an organic electroluminescent device by a wet film formation method, all materials to be used need to be dissolved in an organic solvent and used as an ink. If the material to be used is poor in solvent solubility, an operation such as heating for a long time is required, so the material may be deteriorated before use. Furthermore, if the uniform state can not be maintained for a long time in the solution state, deposition of the material from the solution occurs, and film formation by an inkjet device or the like becomes impossible.
The materials used in the wet film formation method are required to have solubility in two senses, that is, quick dissolution in an organic solvent and maintenance of a uniform state without precipitation after dissolution.

In recent years, the demand for higher density of the ink is increasing. This is achieved by extending the drive life of the device or optimizing the optical design of the device by forming a thicker light emitting layer using a high concentration of ink, so that the so-called microcavity effect is effectively exhibited. This is because improvements have been made to improve color purity and the like.
Therefore, a material for wet film formation of an organic electroluminescent element is required to have higher solvent solubility than that of the prior art.

As a high performance light emitting material applied to a wet film formation method, there is a phosphorescent iridium complex compound having high light emission efficiency. Attempts have been made to improve the color tone, the luminous efficiency and the device driving life by devising the ligand of the iridium complex compound (for example, Patent Documents 1 to 7 and Non-patent Document 1).

International Publication No. 2015/087961 JP, 2016-64998, A International Publication No. 2014/024889 JP 2006-151888 A JP 2002-332291 A US Patent Application Publication No. 2016/0351835 US Patent Application Publication No. 2016/0233442

Since the iridium complex compound generally has poor solvent solubility, it is necessary to introduce solvent-rich solubility to the ligand by introducing a substituent having high flexibility.
On the other hand, it is necessary to introduce a substituent for wavelength adjustment into the ligand in order to make the emission color of the organic electroluminescent element the intended color tone. The latter is particularly important in materials having a longer wavelength than green, in particular, a red iridium light-emitting material that requires a maximum of 600 nm or more of the emission wavelength.

In the case of conventional red light emitting iridium complexes, high solvent solubility can not be obtained when the number of substituents is large and the combination of their positions and types or ligands themselves is not appropriate.
Guides for material design compatible with solubility and desired chromaticity have not yet been sufficiently obtained.

In organic EL lighting, further improvement of color reproducibility is being studied. Under the light source having more wavelength components, color reproducibility is improved. Increasing the width of the light emission spectrum of the light emitting material, in other words, development of a light emitting material having a wider half width of the light emission spectrum is required.

Although the inventors of the present invention synthesized iridium complex compounds referring to the structures specifically disclosed in Patent Documents 3 to 5 and examined the performance as a red light emitting material, improvement in solvent solubility was found as a result. The results suggest that the light emission quantum yield is lowered and the light emission characteristics of the organic EL material may be impaired.
The iridium complex compounds specifically described in Patent Documents 6 and 7 do not exhibit high solvent solubility because the condensed ring structure is too large.

The inventors found that the conventional red light emitting material has insufficient solvent solubility for use in the wet film forming method and has a low luminescence quantum yield, so that the iridium complex compound has high solubility in the solvent, iridium complex It has been found that it is necessary to further improve the storage stability of the composition containing the compound and the solvent and the improvement of the luminous efficiency of the organic electroluminescent device containing the iridium complex compound.

An object of the present invention is to provide an iridium complex compound capable of achieving both high solvent solubility and target chromaticity. In particular, it is an object of the present invention to provide an iridium complex compound having both high solvent solubility and red light emission. Another object of the present invention is to provide an iridium complex compound having a wide half value width of emission spectrum and capable of enhancing a color reproduction rate when used for an illumination application, in addition to the above features.
Another object of the present invention is to provide an iridium complex compound suitable as a light emitting material of a wet film formation type organic electroluminescent device capable of simultaneously achieving high solvent solubility, storage stability and light emitting characteristics.

The present inventor has found that an iridium complex compound having a specific chemical structure exhibits extremely high solvent solubility as a red light emitting material as compared to conventional materials.
Furthermore, it has been found that an iridium complex compound having a specific chemical structure broadens the half bandwidth of the emission spectrum as a red light emitting material as compared with a conventional material.
In addition, it has been found that an iridium complex compound having a specific chemical structure is excellent in storage stability and shows highly efficient light emission.

That is, the gist of the present invention is as follows.

[1] An iridium complex compound represented by the following formula (1).

[In formula (1), Ir represents an iridium atom,
C ¹ to C ⁶ represent carbon atoms, and N ¹ and N ² represent nitrogen atoms.
R ¹ to R ⁴ each independently represent a hydrogen atom or a substituent,
and a, b, c and d respectively represent the maximum number of integers that can be substituted on the rings Cy ¹ , Cy ² , Cy ³ and Cy ⁴ ,
m and n represent 1 or 2, and m + n is 3.
The ring Cy ¹ is a fluorene structure represented by the following formula (2) or (2 ′),

When the ring Cy ¹ is represented by the formula (2), the ring Cy ² is a quinoline or naphthyridine structure represented by any one of the following formulas (3) to (5):
When the ring Cy ¹ is represented by the formula ( ^{2 ′} ), the ring Cy ² is a naphthyridine structure represented by any one of the following formulas (3) to (5):

X ¹ to X ^{18 in} formulas (3) to (5) each independently represent a carbon atom or a nitrogen atom,
Ring Cy ³ represents an aromatic ring or heteroaromatic ring containing carbon atoms C ⁴ and C ⁵ ,
The ring Cy ⁴ represents a heteroaromatic ring containing carbon atom C ⁶ and nitrogen atom N ² . ]

[2] The iridium complex compound according to [1], in which ring Cy ⁴ is a structure represented by the following formula (6).

[In formula (6),
And each of X ¹⁹ to X ²² independently represents a carbon atom or a nitrogen atom,
Y represents N (-R ⁵ ), an oxygen atom or a sulfur atom, and R ⁵ represents a hydrogen atom or a substituent. ]

[3] The iridium according to [1] or [2], wherein ring Cy ¹ is a fluorene structure represented by formula (2), and ring Cy ³ is a compound represented by the following formula (8) Complex compound.

[4] The iridium complex compound according to any one of [1] to [3], wherein Y in the formula (6) is a sulfur atom.

[5] The iridium complex compound according to any one of [1] to [4], wherein the number of nitrogen atoms constituting ring Cy ² is 2.

[6] A composition comprising the iridium complex compound according to any one of [1] to [5] and a solvent.

[7] An organic electroluminescent device comprising the iridium complex compound according to any one of [1] to [5].

[8] A display device having the organic electroluminescent device according to [7].

[9] A lighting device comprising the organic electroluminescent device according to [7].

[10] An iridium complex compound represented by the following formula (7).

[In Formula (7), Ir represents an iridium atom.
C ⁷ to C ⁹ represent carbon atoms, and N ³ and N ⁴ represent nitrogen atoms.
Ring Cy ⁵ represents an aromatic ring or heteroaromatic ring containing carbon atoms C ⁷ and C ⁸ ,
Ring Cy ⁶ represents a heteroaromatic ring containing carbon atom C ⁹ and nitrogen atom N ³ ,
X ²³ to X ²⁶ each independently represent a carbon atom which may have a substituent, or a nitrogen atom,
Y ² represents an oxygen atom, a sulfur atom or a selenium atom,
Each of R ¹⁰ to R ¹² independently represents a hydrogen atom or a substituent.
a ′ and b ′ represent the maximum number of integers that can be substituted on the rings Cy ⁵ and Cy ⁶ respectively, and c ′ is 8.
m 'and n' represent 1 or 2, and m '+ n' is 3. ]

The iridium complex compound of the present invention has high solvent solubility, so that it is possible to manufacture an organic electroluminescent device by a wet film formation method. The organic electroluminescent device of the present invention is useful for organic EL display devices and lighting devices.
In addition, the iridium complex compound of the present invention has a wider half width of the emission spectrum as a red light emitting material as compared with a conventional material, and can increase the color reproduction rate when used for lighting applications.
In addition, the iridium complex compound of the present invention can provide an organic electroluminescent device having a high luminescence quantum yield and excellent luminescence characteristics.

FIG. 1 is a cross-sectional view schematically showing an example of the structure of the organic electroluminescent device of the present invention. FIG. 2 is a graph showing the relationship between the maximum emission wavelength and the half width of the compounds of Examples 3 and 4 and Comparative Examples 3 and 4. FIG. 3 is a graph showing the relationship between the maximum emission wavelength and the emission quantum yield of the compounds of Example 5 and Comparative Examples 5 to 7.

Hereinafter, the embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the present invention.

In the present specification, "aromatic ring" refers to "aromatic hydrocarbon ring" and is distinguished from "heteroaromatic ring" containing a hetero atom as a ring constituent atom. Likewise, "aromatic group" refers to "aromatic hydrocarbon ring group", and "heteroaromatic group" refers to "heteroaromatic ring group".

[Iridium complex compound]
The iridium complex compound of the present invention is a compound represented by the following formula (1).

[In formula (1), Ir represents an iridium atom,
C ¹ to C ⁶ represent carbon atoms, and N ¹ and N ² represent nitrogen atoms.
R ¹ to R ⁴ each independently represent a hydrogen atom or a substituent,
and a, b, c and d respectively represent the maximum number of integers that can be substituted on the rings Cy ¹ , Cy ² , Cy ³ and Cy ⁴ ,
m and n represent 1 or 2, and m + n is 3. ]

The reason why the iridium complex compound of the present invention achieves both high solvent solubility and target chromaticity is presumed as follows.

It is preferable to introduce a fluorene skeleton into the ligand because the emission wavelength can be easily made into the target red region by combination with the ring Cy ² skeleton, but conversely, the free rotational movement of the two benzene rings is inhibited. Due to the extremely flat structure, the solubility in a solvent and the dissolution stability in maintaining a uniform state as an ink and not causing precipitation are generally extremely deteriorated. In order to improve the solvent solubility, for example, a long chain alkyl group or the like is introduced at the 9 position of fluorene, but when such a material is used as a light emitting material of an organic electroluminescent device, it has an insulating property. It is expected that the long-chain alkyl group of the compound significantly blocks the HOMO orbital of the complex molecule, thereby inhibiting the oxidation of the molecule and making charge recombination on the complex less likely to occur, resulting in deterioration of the device performance.

As one of the preferable forms of the present invention, by combining specific ligands into heteroleptic type, it is possible to improve solvent solubility without necessarily requiring the long chain alkyl group. Can be mentioned.

The reason why the iridium complex compound of the present invention achieves both high solvent solubility and light emission quantum yield is presumed as follows.

In order to improve the quantum yield, it is necessary to increase the phosphorescence rate constant kr of the light emitting material. For that purpose, the chemical structure is made rigid and energy dissipation to thermal vibration is prevented, the electron-withdrawing substituent is introduced into the ligand, and LUMO is lowered to enhance the MLCT property of the excited state. The method is used.
From this point of view, for example, the fluorene structure is considered to be preferable since it is fairly rigid since two benzene rings are directly bonded to each other and two methylene groups which may have a substituent. If the rigid structure is too large, the interaction between molecules becomes strong and the solubility is greatly impaired. Therefore, it is necessary to avoid introducing a condensed ring structure to the fluorene ring. Although the fluorene group itself is considered to have some electron donating properties due to the presence of the methylene group, as in the iridium complex compound which is one of the other preferable forms of the present invention, a heteroaromatic ring is placed at the 3-position of the fluorene ring. If it has a ligand structure, the conjugation is not strong because the two aromatic rings of the heteroaromatic ring and the fluorene ring are not on a straight line, and the LUMO of the ligand is not lowered and the MLCT property is kept high.

<Ring Cy ¹ >
The ring Cy ¹ is a structure represented by the following formula (2) or (2 ′) containing carbon atoms C ¹ and C ² coordinated to an iridium atom. In the following formulas (2) and (2 ′), the substituent (R ¹ ) _a − is omitted, but as shown in the specific example of the iridium complex compound of the present invention described later, the ring Cy ¹ Is preferably a 9,9-dimethylfluorene ring, including the substituent (R ¹ ) _a- .

In the case where the high solvent solubility of the iridium complex compound of the present invention and the target chromaticity are particularly compatible, the ring Cy ¹ is preferably a structure represented by Formula (2). In the case where the high solvent solubility and emission quantum yield of the iridium complex compound of the present invention are particularly compatible, the ring Cy ¹ is preferably a structure represented by Formula (2 ′).

<Ring Cy ² >
The ring Cy ² is a structure represented by any one of the following formulas (3) to (5). When ring Cy ¹ is a structure represented by formula (2), ring Cy ² is preferably a quinoline or naphthyridine structure represented by any of the following formulas (3) to (5). When the ring Cy ¹ is a structure represented by the formula ( ² ′), the ring Cy ² is preferably a naphthyridine structure represented by any one of the following formulas (3) to (5).
In the following formulas (3) to (5), the substituent (R ² ) _b -is omitted.

X ¹ to X ^{18 in} formulas (3) to (5) each independently represent a carbon atom or a nitrogen atom.

The number of nitrogen atoms contained in the ring Cy ² is preferably 3 or less, more preferably 2 or less, including the nitrogen atom N ¹ . When the number of nitrogen atoms is 3 or less, the HOMO and LUMO of the iridium complex compound do not become too deep, and both holes and electrons are easily injected into the complex molecule. Therefore, recombination is less likely to occur, which tends to be preferable as a light emitting material of the organic electroluminescent device.

Among the above structures, the ring Cy ² is preferably a structure represented by the formula (3) or the formula (5) from the viewpoint of showing preferable chromaticity of red light emission in the organic EL display, and the formula (3) The structure is particularly preferred. From the viewpoint of enhancing color purity as red and the viewpoint of enhancing MLCT property by making the ligand more electron attractive, the ring Cy ² is more than a quinoline structure in which the nitrogen atom constituting the ring is only N ^1. It is preferable that it is a naphthyridine structure, such as quinazoline and quinoxaline, whose nitrogen atom which comprises a ring is N ¹ and is two.

<Ring Cy ³ >
Ring Cy ³ represents an aromatic ring or a heteroaromatic ring containing carbon atoms C ⁴ and C ⁵ coordinating to the iridium atom.

The ring Cy ³ may be a single ring or may be a fused ring to which a plurality of rings are linked. In the case of a fused ring, the number of rings is not particularly limited, but 6 or less is preferable, and 5 or less is preferable because it tends not to impair the solvent solubility of the complex.

Although there is no particular limitation, when the ring Cy ³ is a heteroaromatic ring, the hetero atom contained in addition to the carbon atom as a ring constituent atom is selected from nitrogen atom, oxygen atom, sulfur atom, silicon atom, phosphorus atom and selenium atom Is preferable from the viewpoint of the chemical stability of the complex.

Specific examples of the ring Cy ³ include, in the aromatic ring, a single-ring benzene ring; two-ring naphthalene ring; three or more rings fluorene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, The chrysene ring, triphenylene ring, fluoranthene ring and the like can be mentioned. In heteroaromatic rings, furan ring of an oxygen-containing atom, benzofuran ring, dibenzofuran ring; thiophene ring of a sulfur-containing atom, benzothiophene ring, dibenzothiophene ring; pyrrole ring of a nitrogen-containing atom, pyrazole ring, imidazole ring, benzimidazole ring, Indole ring, indazole ring, carbazole ring, indolocarbazole ring, indenocarbazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, cinnoline ring, phthalazine ring, quinoxaline ring, quinazoline Ring, quinazolinone ring, acridine ring, phenanthridine ring, carboline ring, purine ring; oxazole ring containing plural kinds of hetero atoms, oxadiazole ring, isoxazole ring, benzoisoxazole ring, thiazole ring, benzothi ring Tetrazole ring, an isothiazole ring, a benzisothiazole ring, and the like.

Among these, in order to control the emission wavelength, improve the solubility in an organic solvent, or improve the durability as an organic electroluminescent device, an appropriate substituent is introduced onto these rings. In many cases, it is preferable that the ring be a known method for introducing such a substituent. Therefore, among the above-mentioned specific examples, it is preferable that one ring constituted by carbon atom C ⁴ directly linked to an iridium atom is a benzene ring. Examples thereof include dibenzofuran ring, dibenzothiophene ring, carbazole ring, indolocarbazole ring, indenocarbazole ring and the like in addition to the above-mentioned aromatic ring. Among these, a benzene ring, a naphthalene ring, a fluorene ring, a dibenzofuran ring, a dibenzothiophene ring and a carbazole ring are more preferable. In particular, from the viewpoint of widening the half width while maintaining solvent solubility, the ring Cy ³ is most preferably a fluorene ring represented by the following formula (8). In the following formula (8), the substituent (R ³ ) _c -is omitted.

The number of atoms constituting the ring Cy ³ is not particularly limited, but from the viewpoint of maintaining the solvent solubility of the iridium complex compound, the number of constituting atoms of the ring is preferably 5 or more, more preferably 6 or more. The number of constituent atoms of the ring is preferably 30 or less, more preferably 20 or less.

<Ring Cy ⁴ >
The ring Cy ⁴ represents a heteroaromatic ring containing a carbon atom C ⁶ and a nitrogen atom N ² coordinating to an iridium atom.

Specific examples of the ring Cy ⁴ include a monocyclic pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, a pyrrole ring, a pyrazole ring, an isoxazole ring, a thiazole ring, an oxazole ring, an oxadiazole ring, Thiazole ring, purine ring; quinoline ring of two ring condensation ring, isoquinoline ring, cinnoline ring, phthalazine ring, quinazoline ring, quinoxaline ring, naphthyridine ring, indole ring, indazole ring, benzoisoxazole ring, benzisothiazole ring, benzimidazole Ring, benzoxazole ring, benzothiazole ring; acridine ring of 3-ring ring ring ring, phenanthroline ring, carbazole ring, carboline ring; benzophenanthricine ring ring of 4 or more rings ring condensed, benzoacridine ring or indolocarboline ring Be Furthermore, carbon atoms that constitute these rings may be further replaced by nitrogen atoms.

Among these, it is easy to introduce a substituent and to easily adjust the emission wavelength and solvent solubility, and from the fact that many methods are known that can be synthesized with good yield when complexed with iridium, ring Cy ⁴ Is preferably a single ring or a fused ring having 4 or less rings, more preferably a single ring or a fused ring having 3 or less rings, and most preferably a single ring or a two-ring fused ring. Specifically, imidazole ring, oxazole ring, thiazole ring, benzimidazole ring, benzoxazole ring, benzothiazole ring, pyridine ring, quinoline ring, isoquinoline ring, pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, cinnoline ring, Phthalazine ring, quinazoline ring, quinoxaline ring or naphthyridine ring is preferable, and further, an imidazole ring, oxazole ring, quinoline ring, isoquinoline ring, pyridazine ring, pyrimidine ring or pyrazine ring is preferable, and in particular, benzoimidazole ring, benzoxazole ring, benzo A thiazole ring, a pyridine ring, an isoquinoline ring, a pyridazine ring, a pyrimidine ring or a pyrazine ring is preferable, and a structure represented by the following formula (6) is most preferable. In formula (6), the substituent (R ⁴ ) _d -is omitted.

X ¹⁹ to X ^{22 in} the formula (6) each independently represent a carbon atom or a nitrogen atom. The preferred number of nitrogen atoms of X ¹⁹ to X ²² is 0 or 1 from the viewpoint of adjusting the emission wavelength particularly to the red region and the ease of synthesis of the complex.

When X ¹⁹ to X ²² are a carbon atom, a hydrogen atom may be bonded to this carbon atom, and those exemplified as the substituents of R ¹ to R ⁵ described later, preferably F, an alkyl group, an aromatic group The group or heteroaromatic group may be substituted. From the viewpoint of not impairing the solubility of the iridium complex compound, the number of atoms constituting the ring Cy ⁴ is preferably 14 or less, more preferably 13 or less.

Y represents N (-R ⁵ ), an oxygen atom or a sulfur atom. R ⁵ represents a hydrogen atom or a substituent.

In Formula (6), the higher the aromaticity of the five-membered ring part is the more chemically stable structure, and is preferable also for the stability of the complex, Y may be N (—R ⁵ ) or a sulfur atom. Preferably it is a sulfur atom.

When R ⁵ is a substituent, it is not particularly limited, but specifically, it has the same meaning as the substituent of R ¹ to R ⁴ described later, and the preferable range is also the same.

<R ¹ to R ⁴ and a to d>
R ¹ to R ⁴ in the formula (1) represent a hydrogen atom or a substituent. R ¹ to R ⁴ are each independently, and may be the same or different.

a to d are integers of the maximum number that can be substituted on the rings Cy ¹ to Cy ⁴ respectively, and a is 8. When a to d are 2 or more, a plurality of R ¹ to R ⁴ may be the same or different.

Two or more adjacent R ¹ to R ⁴ may be bonded to each other to form an aliphatic or aromatic or heteroaromatic single ring or a fused ring, but the decrease in solvent solubility is suppressed Preferably, R ¹ is such that two or more adjacent R ^{1 's} combine with each other to form an aliphatic, aromatic or heteroaromatic, and are not fused to the ring Cy ¹ .

When R ¹ to R ⁴ are a substituent, the type thereof is not particularly limited, and precise control of the target emission wavelength, compatibility with the solvent used, compatibility with the host compound in forming an organic electroluminescent device, etc. An optimal substituent can be selected in consideration of Preferred substituents for the optimization studies are the ranges described below.

R ¹ to R ⁴ are each independently a hydrogen atom, D, F, Cl, Br, I, -N (R ') ₂ , -CN, -NO ₂ , -OH, -COOR', -C (= O) R ', -C (= O) NR', -P (= O) (R ') ₂ , -S (= O) R', -S (= O) ₂ R ', -OS (= O ₂ ) R ′ is a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms, a linear, branched or cyclic alkoxy group having 1 to 30 carbon atoms, a linear chain having 1 to 30 carbon atoms, Branched or cyclic alkylthio group, linear or branched alkenyl group having 2 to 30 carbon atoms, linear or branched or cyclic alkynyl group having 2 to 30 carbon atoms, aromatic group having 5 to 60 carbon atoms A heteroaromatic group having 5 to 60 carbon atoms, an aryloxy group having 5 to 40 carbon atoms, and 5 to 40 carbon atoms The arylthio group, the aralkyl group having 5 to 60 carbon atoms, the heteroaralkyl group having 5 to 60 carbon atoms, the diarylamino group having 10 to 40 carbon atoms, the arylheteroarylamino group having 10 to 40 carbon atoms, or carbon It is selected from several tens to forty di-heteroarylamino groups.

The alkyl group, the alkoxy group, the alkylthio group, the alkenyl group and the alkynyl group may be further substituted by one or more R ′, and one —CH ₂ — group or two or more in these groups Non-adjacent -CH ₂ -groups of -C (-R ') = C (-R')-, -C≡C-, -Si (-R ') _2- , -C (= O) -, -NR'-, -O-, -S-, -CONR'- or a divalent aromatic group may be substituted. One or more hydrogen atoms in these groups may be substituted by D, F, Cl, Br, I or -CN.

The aromatic group, the heteroaromatic group, the aryloxy group, the arylthio group, the aralkyl group, the heteroaralkyl group, the diarylamino group, the arylheteroarylamino group and the diheteroarylamino group respectively Independently, it may be further substituted by one or more R ′.

R 'will be described later.

Examples of the linear, branched or cyclic alkyl group having 1 to 30 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an n-pentyl group and an n-hexyl group Examples include n-octyl group, 2-ethylhexyl group, isopropyl group, isobutyl group, cyclopentyl group, cyclohexyl group, n-octyl group, norbornyl group, adamantyl group and the like. From the viewpoint of durability, the number of carbon atoms is preferably 1 or more, preferably 30 or less, more preferably 20 or less, and most preferably 12 or less.

Examples of the linear, branched or cyclic alkoxy group having 1 to 30 carbon atoms include methoxy, ethoxy, n-propyloxy, n-butoxy, n-hexyloxy, isopropyloxy and cyclohexyloxy And 2-ethoxyethoxy and 2-ethoxyethoxyethoxy groups. From the viewpoint of durability, the number of carbon atoms is preferably 1 or more, preferably 30 or less, more preferably 20 or less, and most preferably 12 or less.

Examples of the linear, branched or cyclic alkylthio group having 1 to 30 carbon atoms include a methylthio group, an ethylthio group, an n-propylthio group, an n-butylthio group, an n-hexylthio group, an isopropylthio group, and a cyclohexylthio group. Examples include 2-methylbutylthio and n-hexylthio. From the viewpoint of durability, the number of carbon atoms is preferably 1 or more, preferably 30 or less, more preferably 20 or less, and most preferably 12 or less.

Examples of linear or branched or cyclic alkenyl groups having 2 to 30 carbon atoms include vinyl, allyl, propenyl, heptenyl, cyclopentenyl, cyclohexenyl and cyclooctenyl groups. From the viewpoint of durability, the number of carbon atoms is preferably 2 or more, preferably 30 or less, more preferably 20 or less, and most preferably 12 or less.

Examples of linear or branched or cyclic alkynyl groups having 2 to 30 carbon atoms include ethynyl group, propionyl group, butynyl group, pentynyl group, hexynyl group, heptynyl group, octynyl group and the like. From the viewpoint of durability, the number of carbon atoms is preferably 2 or more, preferably 30 or less, more preferably 20 or less, and most preferably 12 or less.

The aromatic group having 5 to 60 carbon atoms and the heteroaromatic group having 5 to 60 carbon atoms may be present as a single ring or a fused ring, and one ring may have another type of aromatic ring The group or heteroaromatic group may be a group formed by bonding or condensation.

Examples of these include phenyl, naphthyl, anthracenyl, benzoanthracenyl, phenanthrenyl, benzophenanthrenyl, pyrenyl, chrysenyl, fluoranthenyl, perylenyl, benzopyrenyl and benzofur. Orantenyl group, naphthacenyl group, pentacenyl group, biphenyl group, terphenyl group, fluorenyl group, spirobifluorenyl group, dihydrophenanthrenyl group, dihydropyrenyl group, tetrahydropyrenyl group, indenofluorenyl group, furyl Group, benzofuryl group, isobenzofuryl group, dibenzofuranyl group, thiophene group, benzothiophenyl group, dibenzothiophenyl group, pyrrolyl group, indolyl group, isoindolyl group, carbazolyl group, benzocarbazolyl group, indolocarbazolyl Le basis Indenocarbazolyl group, pyridyl group, cinnoyl group, isocinnolyl group, acridyl group, phenanthridyl group, phenothiazinyl group, phenoxazyl group, pyrazolyl group, indazolyl group, imidazolyl group, benzimidazolyl group, naphthoimidazolyl group, phenanthroimidazolyl Group, pyridine imidazolyl group, oxazolyl group, benzoxazolyl group, naphthoxazolyl group, thiazolyl group, benzothiazolyl group, pyrimidyl group, benzopyrimidyl group, pyridazinyl group, quinoxalinyl group, diazaanthracenyl group, diazapyrenyl group, pyrazinyl Group, phenoxazinyl group, phenothiazinyl group, naphthyridinyl group, azacarbazolyl group, benzocarbolinyl group, phenanthrolinyl group, triazolyl group, benzotriazolyl group, Diazolyl group, thiadiazolyl group, triazinyl group, 2,6-diphenyl-1,3,5-triazin-4-yl group, a tetrazolyl group, purinyl group, etc. benzothiadiazolyl group.

From the viewpoint of the balance between solubility and durability, the carbon number of these groups is preferably 5 or more, preferably 50 or less, more preferably 40 or less, and most preferably 30 or less. preferable.

Examples of the aryloxy group having 5 to 40 carbon atoms include a phenoxy group, a methylphenoxy group, a naphthoxy group, a methoxyphenoxy group and the like. From the viewpoint of the balance between solubility and durability, the carbon number of these aryloxy groups is preferably 5 or more, preferably 30 or less, more preferably 25 or less, and most preferably 20 or less.

Examples of the arylthio group having 5 to 40 carbon atoms include a phenylthio group, a methylphenylthio group, a naphthylthio group, a methoxyphenylthio group and the like. From the viewpoint of the balance between solubility and durability, the carbon number of these arylthio groups is preferably 5 or more, preferably 30 or less, more preferably 25 or less, and most preferably 20 or less.

Examples of the aralkyl group having 5 to 60 carbon atoms include a 1,1-dimethyl-1-phenylmethyl group, a 1,1-di (n-butyl) -1-phenylmethyl group and a 1,1-di (n) group. -Hexyl) -1-phenylmethyl group, 1,1-di (n-octyl) -1-phenylmethyl group, phenylmethyl group, phenylethyl group, 3-phenyl-1-propyl group, 4-phenyl-1-phenyl group n-butyl group, 1-methyl-1-phenylethyl group, 5-phenyl-1-n-propyl group, 6-phenyl-1-n-hexyl group, 6-naphthyl-1-n-hexyl group, 7- Examples include phenyl-1-n-heptyl group, 8-phenyl-1-n-octyl group, 4-phenylcyclohexyl group and the like. From the viewpoint of the balance between solubility and durability, the carbon number of these aralkyl groups is preferably 5 or more, and more preferably 40 or less.

Examples of heteroaralkyl groups having 5 to 60 carbon atoms include a 1,1-dimethyl-1- (2-pyridyl) methyl group and 1,1-di (n-hexyl) -1- (2-pyridyl) methyl Group, (2-pyridyl) methyl group, (2-pyridyl) ethyl group, 3- (2-pyridyl) -1-propyl group, 4- (2-pyridyl) -1-n-butyl group, 1-methyl- 1- (2-pyridyl) ethyl group, 5- (2-pyridyl) -1-n-propyl group, 6- (2-pyridyl) -1-n-hexyl group, 6- (2-pyrimidyl) -1- group n-hexyl group, 6- (2,6-diphenyl-1,3,5-triazin-4-yl) -1-n-hexyl group, 7- (2-pyridyl) -1-n-heptyl group, 8 -(2-pyridyl) -1-n-octyl group, 4- (2-pyridyl) cyclohexyl group And the like. From the viewpoint of the balance between solubility and durability, the carbon number of these heteroaralkyl groups is preferably 5 or more, preferably 50 or less, more preferably 40 or less, and 30 or less. Is most preferred.

Examples of the diarylamino group having 10 to 40 carbon atoms include a diphenylamino group, a phenyl (naphthyl) amino group, a di (biphenyl) amino group, and a di (p-terphenyl) amino group. From the viewpoint of the balance between solubility and durability, the carbon number of these diarylamino groups is preferably 10 or more, preferably 36 or less, more preferably 30 or less, and 25 or less. Is most preferred.

Examples of the arylheteroarylamino group having 10 to 40 carbon atoms include phenyl (2-pyridyl) amino group, phenyl (2,6-diphenyl-1,3,5-triazin-4-yl) amino group and the like It can be mentioned. From the viewpoint of the balance between solubility and durability, the carbon number of these arylheteroarylamino groups is preferably 10 or more, preferably 36 or less, more preferably 30 or less, and 25 or less. Most preferably.

Examples of the diheteroarylamino group having 10 to 40 carbon atoms include di (2-pyridyl) amino group and di (2,6-diphenyl-1,3,5-triazin-4-yl) amino group. . From the viewpoint of the balance between solubility and durability, the carbon number of these diheteroarylamino groups is preferably 10 or more, preferably 36 or less, more preferably 30 or less, and 25 or less. Most preferably.

R ¹ to R ⁴ each independently represent a hydrogen atom, F, -CN, a linear or branched C 1 -C 30 chain, from the viewpoint of not impairing the durability as a light emitting material in an organic electroluminescent device. Or a cyclic alkyl group, an aryloxy group having 5 to 40 carbon atoms, an arylthio group having 5 to 40 carbon atoms, a diarylamino group having 10 to 40 carbon atoms, an aralkyl group having 5 to 60 carbon atoms, 5 carbon atoms An aromatic group having 60 or less and a heteroaromatic group having 5 to 60 carbon atoms are preferable, and a hydrogen atom, F, -CN, an alkyl group, an aralkyl group, an aromatic group or a heteroaromatic group is particularly preferable, and a hydrogen atom , F, -CN, an alkyl group, an aromatic group and a heteroaromatic group are most preferable.

When R ¹ to R ⁴ are substituents, the substitution position is not particularly limited. However, R ³ is a substituent, when the ring Cy ³ is a benzene ring, particularly when emphasis on durability of the complex, at least one of R ³ in the 4-position or 5-position of the benzene ring substituted It is preferable to be substituted, and more preferable to be substituted at the 4-position. In this case, R ³ is preferably the above-mentioned aromatic group or heteroaromatic group.

When a nitrogen atom which is not coordinated to the iridium atom in the ring Cy ² is present, at least one R ² substituent is preferably present at a position adjacent to the nitrogen atom. In this case, by shielding the nitrogen atom by steric hindrance, there is a tendency to be able to alleviate the external influence such as solvation and to suppress the influence on the emission wavelength and other physical properties.

<R '>
Wherein each R 'is independently a hydrogen atom, D, F, Cl, Br , I, -N (R'') 2, -CN, -NO 2, -Si (R'') 3, -B (OR'') ₂ , -C (= O) R'', -P (= O) (R'') ₂ , -S (= O) ₂ R'', -OSO ₂ R'', having 1 to 30 carbon atoms The following linear, branched or cyclic alkyl group, linear or branched alkoxy group having 1 to 30 carbon atoms, linear or branched alkyl cyclic group having 1 to 30 carbon atoms, 2 or more carbon atoms 30 or less linear, branched or cyclic alkenyl groups, 2 to 30 carbon atoms, linear, branched or cyclic alkynyl groups, 5 to 60 carbon atoms, aromatic groups, 5 to 60 carbon atoms Group, aryloxy group having 5 to 40 carbon atoms, arylthio group having 5 to 40 carbon atoms, 5 or more carbon atoms An aralkyl group of 0 or less, a heteroaralkyl group having 5 to 60 carbon atoms, a diarylamino group having 10 to 40 carbon atoms, an arylheteroarylamino group having 10 to 40 carbon atoms, or a dihetero having 10 to 40 carbon atoms It is selected from an arylamino group.

The alkyl group, the alkoxy group, the alkylthio group, the alkenyl group and the alkynyl group may be further substituted by one or more R ′ ′, and one —CH ₂ — group in these groups or 2 The above non-adjacent -CH ₂ -group is -C (-R '') = C (-R '')-, -C≡C-, -Si (-R '') _2- , -C (= O)-, -NR ''-, -O-, -S-, -CONR ''-or a divalent aromatic group may be substituted. In addition, one or more hydrogen atoms in these groups may be substituted with D, F, Cl, Br, I or -CN.

Also, the aromatic group, the heteroaromatic group, the aryloxy group, the arylthio group, the aralkyl group, the heteroaralkyl group, the diarylamino group, the arylheteroarylamino group and the diheteroarylamino group , And may be further substituted by one or more R ′ ′. The details of R ′ ′ will be described later.

In addition, two or more adjacent R's may be bonded to each other to form an aliphatic or aromatic or heteroaromatic single ring or fused ring.

All the examples of the above-mentioned groups are as defined in the section of R ¹ to R ⁴ .

<R ''>
R ′ ′ each independently represents a hydrogen atom, D, F, —CN, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, an aromatic group having 1 to 20 carbon atoms, or a complex having 1 to 20 carbon atoms It is selected from aromatic groups.

Two or more adjacent R ′ ′ may bond to each other to form an aliphatic or aromatic or heteroaromatic single ring or fused ring.

<Combination of ring Cy ³ and ring Cy ^4>
The combination of the ring Cy ³ and the ring Cy ⁴ as an auxiliary ligand capable of widening the half bandwidth in the emission spectrum and exhibiting the most preferable performance as a lighting application is 2- (9H-fluoren-2-yl) benzothiazole .

<Specific example>
Preferred specific examples of the iridium complex compound of the present invention other than those shown in the following examples are shown below, but the present invention is not limited thereto.

<New iridium complex compounds>
The present invention provides a novel iridium complex compound represented by the following formula (7).

[In Formula (7), Ir represents an iridium atom.
C ⁷ to C ⁹ represent a carbon atom,
N ³ and ^{N 4} represents a nitrogen atom.
Ring Cy ⁵ represents an aromatic ring or heteroaromatic ring containing carbon atoms C ⁷ and C ⁸ ,
The ring Cy ⁶ represents a heteroaromatic ring containing a carbon atom C ⁹ and a nitrogen atom N ^3, and X ²³ to X ²⁶ each independently represent a carbon atom which may have a substituent, or a nitrogen atom,
Y ² represents an oxygen atom, a sulfur atom or a selenium atom,
Each of R ¹⁰ to R ¹² independently represents a hydrogen atom or a substituent.
a ′ and b ′ represent the maximum number of integers that can be substituted on the rings Cy ⁵ and Cy ⁶ respectively, and c ′ is 8.
m 'and n' represent 1 or 2, and m '+ n' is 3. ]

The iridium complex compound represented by the formula (7) can improve solvent solubility without necessarily requiring a long-chain alkyl group by combining specific ligands into a heteroleptic type. it can.

The inventors of the present invention have found that particularly in the case of having a fluorene structure having R ¹² as an auxiliary ligand ring in the formula (7), the half bandwidth of the emission spectrum is broadened. In particular, it has been found that this is particularly remarkable when the ring having the nitrogen atom N ⁴ is a benzothiazole ring, regardless of the type of main ligand ring Cy ⁵ and the ring Cy ⁶ .
Although the reason for this phenomenon is not clear, when the excited state electron is deactivated by the HOMO level on the auxiliary ligand side becoming shallow, it partially transits to the orbital on the auxiliary ligand side as well. In order to compete with the transition in the order, we speculate that it is to show light emission by multiple energy gaps.

<Ring Cy ⁵ >
Ring Cy ⁵ represents an aromatic ring or a heteroaromatic ring containing carbon atoms C ⁷ and C ⁸ coordinating to the iridium atom. Specific examples and preferred ranges are the same as the ring Cy ³ of formula (1). Among these, the fluorene structure represented by Formula (2) mentioned as ring Cy ¹ of Formula (1) is particularly preferable.

<Ring Cy ⁶ >
The ring Cy ⁶ represents a heteroaromatic ring containing a carbon atom C ⁹ coordinating to an iridium atom and a nitrogen atom N ³ . Specific examples thereof include those shown as the heteroaromatic ring of the ring Cy ³ of the formula (1). Among these, heteroaromatic rings mentioned as ring Cy ² of formula (1) are particularly preferable.

<X ²³ to X ²⁶ >
Each of X ²³ to X ²⁶ independently represents a carbon atom or a nitrogen atom. From the viewpoint of adjusting the emission wavelength particularly to the red region and the ease of synthesis of the complex, the preferred number of nitrogen atoms among X ²³ to X ²⁶ is 0 or 1.

When X ²³ to X ²⁶ are a carbon atom, a hydrogen atom may be bonded to this carbon atom, and those exemplified as the aforementioned substituent of R ¹ to R ⁴ , preferably F, an alkyl group, an aromatic group The group or heteroaromatic group may be substituted. From the viewpoint of not impairing the solubility of the iridium complex compound, the number of atoms constituting the benzothiazole ring containing X ²³ to X ²⁶ is preferably 13 or less.

<Y ² >
Y ² represents an oxygen atom, a sulfur atom or a selenium atom. From the viewpoint of the stability of the complex, Y ² is preferably a sulfur atom.

<R ¹⁰ to R ¹² >
R ¹⁰ to R ¹² represent a hydrogen atom or a substituent. R ¹⁰ to R ¹² are each independently, and may be the same or different.

a ′ and b ′ represent the maximum number of integers that can be substituted on the rings Cy ⁵ and Cy ⁶ respectively, and c ′ is 8.

When there are a plurality of R ¹⁰ to R ¹² , they may be the same or different.
Two or more adjacent R ¹⁰ to R ¹² may be bonded to each other to form an aliphatic or aromatic or heteroaromatic single ring or a fused ring.

Specific examples of the substituents of R ¹⁰ to R ¹² and preferred examples thereof are the same as R ¹ to R ⁴ in formula (1).

<Maximum emission wavelength>
The iridium complex compound of the present invention can make the emission wavelength longer. The index indicating the length of the emission wavelength is preferably 580 nm or more, more preferably 590 nm or more, still more preferably 600 nm or more, still more preferably 700 nm or less, and most preferably 680 nm or less. When the maximum emission wavelength is in this range, it tends to be able to express the preferable color of the red light emitting material suitable as the organic electroluminescent element.

(How to measure the maximum emission wavelength)
A solution of an iridium complex compound dissolved in 2-methyltetrahydrofuran at a concentration of 1 × 10 ^-4 mol / L or less at normal temperature using a spectrophotometer (manufactured by Hamamatsu Photonics Co., Ltd., organic EL quantum yield measurement device C9920-02) Measure the phosphorescence spectrum. The wavelength showing the maximum value of the obtained phosphorescence spectrum intensity is taken as the maximum emission wavelength.

<Method of synthesizing iridium complex compound>
<Method of synthesizing ligand>
The ligand of the iridium complex compound of the present invention can be synthesized by a combination of known methods and the like. In particular, the fluorene ring of ring Cy ¹ is easily introduced, for example, by using a compound having bromine, -B (OH) ₂ group, an acetyl group or a carboxy group at the 2- or 3-position of the fluorene ring as a raw material it can.

Synthesis of a ligand containing a ring Cy ¹ and a ring Cy ² may be carried out by further subjecting these raw materials to Suzuki-Miyaura coupling reaction with halogenated quinolines, 2-formyl or acylanilines, or acyls in an ortho position to each other. They can be synthesized by known reactions such as Friedlaender cyclization reaction (Chem. Rev. 2009, 109, 2652 or Organic Reactions, 28 (2), 37-201) with aminopyridines and the like.

<Method of synthesizing iridium complex compound>
The iridium complex compound of the present invention can be synthesized by a combination of known methods and the like. Details will be described below.

As a synthesis method of the iridium complex compound, a method via a chlorine-bridged iridium binuclear complex as shown in the following formula [A] using a phenylpyridine ligand as an example for the sake of clarity (M. G. Colombo , T. C. Brunold, T. Riedener, H. U. Gudel Inorg. Chem., 1994, 33, 545-550), a chlorine bridge is further exchanged with acetylacetonate from the following formula [B] dinuclear complex, and mononuclear Method for obtaining the desired substance after conversion to a complex (S. Lamansky, P. Djurovich, D. Murphy, F. Abdel-Razzaq, R. Kwong, I. Tsyba, M. Borz, B. Mui, R. Bau, M. Thompson, Inorg. Chem., 2001, 40, 1704-1711). Although but it can be exemplified, but the invention is not limited thereto.

For example, conditions of a typical reaction represented by the following formula [A] are as follows.
As a first step, a chlorine-bridged iridium binuclear complex is synthesized by the reaction of two equivalents of the first ligand and one equivalent of iridium chloride n-hydrate. As the solvent, a mixed solvent of 2-ethoxyethanol and water is usually used, but no solvent or another solvent may be used. The reaction can also be promoted by using an excess amount of a ligand or using an additive such as a base. Instead of chlorine, other crosslinkable anionic ligands such as bromine can also be used.

The reaction temperature is not particularly limited, but generally, 0 ° C. or more is preferable, and 50 ° C. or more is more preferable. Moreover, 250 degrees C or less is preferable and 150 degrees C or less is more preferable. When the reaction temperature is in this range, only the desired reaction proceeds without by-products or decomposition reactions, and high selectivity tends to be obtained.

In the second step, a halide ion scavenger such as silver trifluoromethanesulfonate is added and brought into contact with the second ligand to obtain the target complex. The solvent is usually ethoxyethanol or diglyme, but depending on the type of ligand, no solvent or other solvent can be used, and a plurality of solvents can be mixed and used. Although the reaction may proceed without the addition of a halogen ion scavenger, it is not always necessary, but in order to selectively synthesize facial isomers having higher reaction yield and higher quantum yield, the scavenger The addition of is preferred. Although the reaction temperature is not particularly limited, the reaction is usually carried out in the range of 0 ° C to 250 ° C.

Typical reaction conditions represented by the following formula [B] will be described.
The first stage binuclear complex can be synthesized in the same manner as in the formula [A].
In the second step, one or more equivalents of a 1,3-dione compound such as acetylacetone and the active hydrogen of the 1,3-dione compound such as sodium carbonate can be extracted to the binuclear complex; The reaction is converted to a mononuclear complex in which a 1,3-dionato ligand is coordinated by reaction with an equivalent or more. Usually, a solvent such as ethoxyethanol or dichloromethane capable of dissolving the starting binuclear complex is used, but if the ligand is liquid, it can be carried out without a solvent. While the reaction temperature is not particularly limited, it is usually carried out in the range of 0 ° C to 200 ° C.

The third step is to react the second ligand with one or more equivalents. The type and amount of solvent are not particularly limited, and may be solventless if the second ligand is liquid at the reaction temperature. The reaction temperature is also not particularly limited, but it is often reacted at a relatively high temperature of 100 ° C. to 300 ° C. because the reactivity is somewhat poor. Therefore, a high boiling point solvent such as glycerin is preferably used.

After the final reaction, purification is performed to remove unreacted starting materials, reaction byproducts and solvents. Although purification procedures in ordinary organic synthesis chemistry can be applied, purification by silica gel column chromatography mainly in normal phase is carried out as described in the above non-patent literature. As a developing solution, single or mixed liquid of hexane, heptane, dichloromethane, chloroform, ethyl acetate, toluene, methyl ethyl ketone and methanol can be used. Purification may be performed multiple times under different conditions. Other chromatography techniques (reverse phase silica gel chromatography, size exclusion chromatography, paper chromatography), and separation operations such as separation washing, reprecipitation, recrystallization, suspension washing of powder, vacuum drying, etc. as necessary. Can be applied.

<Uses of iridium complex compounds>
The iridium complex compound of the present invention can be suitably used as a material used for an organic electroluminescent device, that is, as a red light emitting material of an organic electroluminescent device, and also as a light emitting material for an organic electroluminescent device and other light emitting devices. It can be used for

[Iridium Complex Compound-Containing Composition]
The iridium complex compound of the present invention is preferably used together with a solvent since it is excellent in solvent solubility. Hereinafter, the composition of the present invention containing the iridium complex compound of the present invention and a solvent (hereinafter sometimes referred to as “iridium complex compound-containing composition”) will be described.

The iridium complex compound containing composition of this invention contains the iridium complex compound of this invention, and a solvent. The iridium complex compound-containing composition of the present invention is generally used to form a layer or a film by a wet film formation method, and is particularly preferably used to form an organic layer of an organic electroluminescent device. The organic layer is particularly preferably a light emitting layer

The iridium complex compound-containing composition is preferably a composition for an organic electroluminescent device, and is particularly preferably used as a composition for forming a light emitting layer.

The content of the iridium complex compound of the present invention in the iridium complex compound-containing composition is usually 0.001% by mass or more, preferably 0.01% by mass or more, and usually 99.9% by mass or less, preferably 99% by mass or less is there. By setting the content of the iridium complex compound in the composition in this range, injection of holes and electrons is efficiently performed from the adjacent layer (for example, the hole transport layer or the hole blocking layer) to the light emitting layer. The drive voltage can be reduced.
The iridium complex compound of the present invention may be contained singly or in combination of two or more kinds in the iridium complex compound-containing composition.

When the iridium complex compound-containing composition is used for, for example, an organic electroluminescent device, the charge transportable compound used in the organic electroluminescent device, particularly the light emitting layer, may be contained in addition to the iridium complex compound of the present invention and the solvent. Good.

When the light emitting layer of an organic electroluminescent device is formed using the iridium complex compound-containing composition of the present invention, the iridium complex compound of the present invention is used as a light emitting material, and another charge transporting compound is used as a charge transporting host material It is preferable to include.

The solvent contained in the iridium complex compound-containing composition of the present invention is a volatile liquid component used to form a layer containing an iridium complex compound by wet film formation.

The solvent is not particularly limited as long as it is an organic solvent in which the charge transport compound described later dissolves well because the iridium complex compound of the present invention, which is a solute, has high solvent solubility.

Preferred solvents include, for example, alkanes such as n-decane, cyclohexane, ethylcyclohexane, decalin and bicyclohexane; aromatic hydrocarbons such as toluene, xylene, mesitylene, phenylcyclohexane and tetralin; chlorobenzene, dichlorobenzene and trichlorobenzene Halogenated aromatic hydrocarbons such as 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, Aromatic ethers such as 2,4-dimethyl anisole, diphenyl ether; Aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, n-butyl benzoate, Alicyclic ketones such as chlorohexanone, cyclooctanone and phencone; alicyclic alcohols such as cyclohexanol and cyclooctanol; aliphatic ketones such as methyl ethyl ketone and dibutyl ketone; aliphatic alcohols such as butanol and hexanol; Aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol-1-monomethyl ether acetate (PGMEA); and the like.

Among them, alkanes and aromatic hydrocarbons are preferable. In particular, phenylcyclohexane has desirable viscosity and boiling point in the wet film formation process.

One of these solvents may be used alone, or two or more thereof may be used in any combination and ratio.

The boiling point of the solvent used is usually 80 ° C. or more, preferably 100 ° C. or more, more preferably 120 ° C. or more, and usually 270 ° C. or less, preferably 250 ° C. or less, more preferably 230 ° C. or less. If it is less than this range, the film formation stability may be reduced by solvent evaporation from the composition during wet film formation.

The content of the solvent in the iridium complex compound-containing composition is preferably 1% by mass or more, more preferably 10% by mass or more, particularly preferably 50% by mass or more, preferably 99.99% by mass or less, more preferably 99 It is not more than 9% by mass, particularly preferably not more than 99% by mass. Usually, the thickness of the light emitting layer is about 3 to 200 nm, but if the content of the solvent is below this lower limit, the viscosity of the composition becomes too high, and the film forming workability may be lowered. If the content of the solvent exceeds this upper limit, the thickness of the film obtained by removing the solvent after film formation can not be obtained, so that film formation tends to be difficult.

As another charge transportable compound which can be contained in the iridium complex compound-containing composition of the present invention, those conventionally used as materials for organic electroluminescent devices can be used. For example, pyridine, carbazole, naphthalene, perylene, pyrene, anthracene, chrysene, naphthacene, phenanthrene, coronene, fluoranthene, benzophenanthrene, fluorene, acetonaphthofluoranthene, coumarin, p-bis (2-phenylethenyl) benzene and those Derivatives, quinacridone derivatives, DCM (4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran) compounds, benzopyran derivatives, rhodamine derivatives, benzothioxanthene derivatives, azabenzothioxanthenes, aryls A fused aromatic ring compound in which an amino group is substituted, a styryl derivative in which an arylamino group is substituted, and the like can be mentioned.

One of these may be used alone, or two or more of them may be used in any combination and ratio.

The content of the other charge transporting compound in the iridium complex compound-containing composition is usually 1000 parts by mass or less, preferably 100 parts by mass, relative to 1 part by mass of the iridium complex compound of the present invention in the iridium complex compound containing composition. Or less, more preferably 50 parts by weight or less, usually 0.01 parts by weight or more, preferably 0.1 parts by weight or more, and more preferably 1 part by weight or more.

If necessary, the iridium complex compound-containing composition of the present invention may further contain other compounds in addition to the above compounds and the like. For example, in addition to the above-mentioned solvents, other solvents may be contained. As another solvent, for example, amides such as N, N-dimethylformamide, N, N-dimethylacetamide and the like, dimethyl sulfoxide and the like can be mentioned. One of these may be used alone, or two or more of them may be used in any combination and ratio.

[Organic electroluminescent device]
The organic electroluminescent device of the present invention comprises the iridium complex compound of the present invention.

The organic electroluminescent device of the present invention preferably has at least an anode, a cathode and at least one organic layer between the anode and the cathode on a substrate, and at least one of the organic layers is the present invention. Iridium complex compounds of The organic layer comprises a light emitting layer.

The organic layer containing the iridium complex compound of the present invention is more preferably a layer formed using the composition of the present invention, and still more preferably a layer formed by a wet film formation method. The layer formed by the wet film formation method is preferably a light emitting layer.

In the present invention, the wet film forming method is a film forming method, that is, as a coating method, for example, spin coating method, dip coating method, die coating method, bar coating method, blade coating method, roll coating method, spray coating method, capillary Apply a wet film forming method such as coating method, inkjet method, nozzle printing method, screen printing method, gravure printing method, flexo printing method, etc., and dry the film formed by these methods to form a film It says how to do it.

FIG. 1 is a schematic cross-sectional view showing a structural example suitable for the organic electroluminescent device 10 of the present invention. In FIG. 1, reference numeral 1 denotes a substrate, 2 denotes an anode, 3 denotes a hole injection layer, 4 denotes a hole transport layer, 5 denotes a light emitting layer, 6 denotes a hole blocking layer, and 7 denotes an electron transport layer. Reference numeral 8 represents an electron injection layer, and reference numeral 9 represents a cathode.

As materials applied to these structures, known materials can be applied, and there is no particular limitation, but representative materials and production methods for each layer will be described below as an example. In the following, when a gazette, a paper or the like is cited, applicable contents can be applied and applied as appropriate within the common sense of those skilled in the art.

<Substrate 1>
The substrate 1 is a support of the organic electroluminescent device, and usually, a plate of quartz or glass, a metal plate or metal foil, a plastic film or sheet, or the like is used. Among these, a glass plate and a plate of a transparent synthetic resin such as polyester, polymethacrylate, polycarbonate or polysulfone are preferable. It is preferable that the substrate 1 be made of a material having high gas barrier properties because deterioration of the organic electroluminescent device due to external air hardly occurs. In particular, in the case of using a material having a low gas barrier property such as a synthetic resin substrate, it is preferable to provide a dense silicon oxide film or the like on at least one side of the substrate 1 to enhance the gas barrier property.

<Anode 2>
The anode 2 has a function of injecting holes into the layer on the light emitting layer side. The anode 2 is usually a metal such as aluminum, gold, silver, nickel, palladium, platinum or the like; a metal oxide such as an oxide of indium and / or tin; a metal halide such as copper iodide; carbon black or poly (3 -Methylthiophene), polypyrrole, and conductive polymers such as polyaniline.

The formation of the anode 2 is usually performed by a dry method such as a sputtering method or a vacuum evaporation method in many cases. When forming the anode 2 using metal fine particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, conductive polymer fine powder, etc., they are dispersed in a suitable binder resin solution It can also be formed by coating on a substrate. In the case of a conductive polymer, the thin film can be formed directly on the substrate by electrolytic polymerization, or the conductive polymer can be coated on the substrate to form the anode 2 (Appl. Phys. Lett., 60 volumes) , 2711 (1992).

The anode 2 usually has a single layer structure, but may have a laminated structure as appropriate. When the anode 2 has a laminated structure, different conductive materials may be laminated on the first-layer anode.

The thickness of the anode 2 may be determined according to the required transparency and the material and the like. In particular, when high transparency is required, the thickness is preferably such that the visible light transmittance is 60% or more, and more preferably 80% or more. The thickness of the anode 2 is usually 5 nm or more, preferably 10 nm or more, and is usually 1000 nm or less, preferably 500 nm or less.
When the transparency is not necessary, the thickness of the anode 2 may be arbitrarily set in accordance with the required strength and the like, and in this case, the anode 2 may have the same thickness as the substrate 1.

When film formation is performed on the surface of the anode 2, the impurities on the anode are removed and the ionization potential is adjusted by performing treatment such as ultraviolet light + ozone, oxygen plasma, argon plasma or the like before film formation. It is preferable to improve the hole injection property.

<Hole injection layer 3>
The layer responsible for transporting holes from the anode 2 side to the light emitting layer 5 side is usually called a hole injecting and transporting layer or a hole transporting layer. When there are two or more layers responsible for transporting holes from the anode 2 side to the light emitting layer 5 side, the layer closer to the anode 2 side may be referred to as a hole injection layer 3. The hole injection layer 3 is preferably used in that it enhances the function of transporting holes from the anode 2 to the light emitting layer 5 side. When the hole injection layer 3 is used, the hole injection layer 3 is usually formed on the anode 2.

The thickness of the hole injection layer 3 is usually 1 nm or more, preferably 5 nm or more, and usually 1000 nm or less, preferably 500 nm or less.

The hole injection layer 3 may be formed by a vacuum evaporation method or a wet film formation method. It is preferable to form by a wet film-forming method at the point which is excellent in the film-forming property.

The hole injecting layer 3 preferably contains a hole transporting compound, and more preferably contains a hole transporting compound and an electron accepting compound. Furthermore, it is preferable to contain a cation radical compound in the hole injection layer 3, and it is particularly preferable to contain a cation radical compound and a hole transporting compound.

(Hole transportable compound)
The composition for forming a hole injection layer usually contains a hole transportable compound to be the hole injection layer 3.
In the case of a wet film formation method, a solvent is usually further contained. The composition for forming a hole injection layer preferably has high hole transportability, and can efficiently transport injected holes. For this reason, it is preferable that the hole mobility is large and that an impurity serving as a trap is unlikely to be generated at the time of production or use. In addition, it is preferable that the stability be excellent, the ionization potential be small, and the transparency to visible light be high. In particular, in the case where the hole injection layer 3 is in contact with the light emitting layer 5, it is preferable that the light emission from the light emitting layer 5 is not quenched or that the light emitting layer 5 forms an exciplex so as not to reduce the light emission efficiency.

From the viewpoint of charge injection barrier from the anode 2 to the hole injection layer 3, the hole transportable compound is preferably a compound having an ionization potential of 4.5 eV to 6.0 eV. Examples of hole transporting compounds include aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzylphenyl compounds, compounds in which tertiary amines are linked by a fluorene group, hydrazones And compounds such as silazane compounds and quinacridone compounds.

Among the above-described exemplified compounds, aromatic amine compounds are preferable, and aromatic tertiary amine compounds are particularly preferable, from the viewpoint of amorphousness and visible light transparency. The aromatic tertiary amine compound is a compound having an aromatic tertiary amine structure, and also includes a compound having a group derived from an aromatic tertiary amine.

The type of aromatic tertiary amine compound is not particularly limited, but a polymer compound having a weight average molecular weight of 1,000 to 1,000,000 (a polymerizable compound in which repeating units are continuous) from the viewpoint of obtaining uniform light emission due to the surface smoothing effect. It is preferred to use As a preferable example of an aromatic tertiary amine polymer compound, the polymer compound etc. which have a repeating unit represented by following formula (I) are mentioned.

(In the formula (I), Ar ¹ and Ar ² are each independently, .Ar ³ representing a good heteroaromatic group optionally having an optionally substituted aromatic group or a substituted group To Ar ⁵ each independently represent an aromatic group which may have a substituent or a heteroaromatic group which may have a substituent Q is selected from the following group of linking groups Among Ar ¹ to Ar ⁵ , two groups bonded to the same N atom may be bonded to each other to form a ring.

The linking group is shown below.

(In the above formulas, Ar 6 ^- Ar ¹⁶ are each independently, .R ^a represents an heteroaromatic group optionally having an optionally substituted aromatic group or a substituted group; Each R ^b independently represents a hydrogen atom or any substituent.)

As the aromatic group and heteroaromatic group of Ar ¹ to Ar ¹⁶ , a benzene ring, a naphthalene ring, a phenanthrene ring, a thiophene ring, a pyridine ring, from the viewpoint of solubility of a polymer compound, heat resistance and hole injection transportability The group derived from is preferable and the group derived from a benzene ring and a naphthalene ring is more preferable.

Specific examples of the aromatic tertiary amine polymer compound having a repeating unit represented by the formula (I) include those described in WO 2005/089024.

(Electron-accepting compound)
The hole injection layer 3 can improve the conductivity of the hole injection layer 3 by oxidation of the hole transport compound, and therefore, preferably contains an electron accepting compound.

The electron accepting compound is preferably a compound having an oxidizing power and capable of accepting one electron from the above-mentioned hole transporting compound, specifically, a compound having an electron affinity of 4 eV or more, and an electron affinity More preferred is a compound having a 5 eV or more.

Such electron accepting compounds include, for example, triaryl boron compounds, metal halides, Lewis acids, organic acids, onium salts, salts of arylamines and metal halides, and salts of arylamines and Lewis acids. One or two or more compounds selected from the group can be mentioned. Specifically, substituted onium salts of organic groups such as 4-isopropyl-4'-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate, triphenylsulfonium tetrafluoroborate, etc. (WO 2005/089024); High valent inorganic compounds such as iron (III) (Japanese Patent Laid-Open No. 11-251067), ammonium peroxodisulfate; cyano compounds such as tetracyanoethylene; tris (pentafluorophenyl) borane (Japanese Patent Laid-Open No. 2003-31365) Aromatic boron compounds such as: fullerene derivatives and iodine.

(Cation radical compound)
As a cation radical compound, the ionic compound which consists of a cation radical which is a chemical species which removed one electron from a hole transportable compound, and counter anion is preferable. When the cation radical is derived from a hole transporting polymer compound, the cation radical has a structure in which one electron is removed from the repeating unit of the polymer compound.

The cation radical is preferably a chemical species obtained by removing one electron from the compound described above as the hole transporting compound. Chemical species obtained by removing one electron from a compound preferable as the hole transporting compound is preferable from the viewpoints of amorphousness, transmittance of visible light, heat resistance, and solubility.

The cation radical compound can be generated by mixing the above-mentioned hole transporting compound and the electron accepting compound. By mixing the above-mentioned hole transporting compound and the electron accepting compound, electron transfer occurs from the hole transporting compound to the electron accepting compound, and it consists of a cation radical and a counter anion of the hole transporting compound. A cation ion compound is formed.

Cationic radical compounds derived from high molecular weight compounds such as PEDOT / PSS (Adv. Mater., 2000, 12, 481) and emeraldine hydrochloride (J. Phys. Chem., 1990, 94, 7716) It is also produced by oxidative polymerization (dehydrogenation polymerization).
The oxidative polymerization referred to herein is to oxidize a monomer chemically or electrochemically in an acidic solution using a peroxodisulfate or the like. In the case of this oxidative polymerization (dehydrogenation polymerization), the monomer is polymerized by oxidation, and the cation radical which is obtained by removing one electron from the repeating unit of the polymer having the anion derived from the acidic solution as a counter anion is Generate

(Formation of hole injection layer 3 by wet film formation method)
In the case of forming the hole injection layer 3 by a wet film formation method, a composition for forming a film (positive film) is usually prepared by mixing the material to be the hole injection layer 3 with a soluble solvent (solvent for the hole injection layer). The composition for forming a hole injection layer is prepared, and the composition for forming a hole injection layer is formed into a film by a wet film formation method on a layer (usually, the anode 2) corresponding to the lower layer of the hole injection layer 3. , Formed by drying. Drying of the formed film can be performed in the same manner as the drying method in the formation of the light emitting layer 5 by a wet film formation method.

The concentration of the hole transporting compound in the composition for forming a hole injection layer is optional as long as the effects of the present invention are not significantly impaired, but a lower one is preferable in terms of film thickness uniformity, and hole injection is preferable. It is preferable that the height is high in that defects in the layer 3 are not easily generated. The concentration of the hole transporting compound in the composition for forming a hole injection layer is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, particularly preferably 0.5% by mass or more, and 70% by mass. % Or less is preferable, 60 mass% or less is more preferable, and 50 mass% or less is particularly preferable.

Examples of the solvent include ether solvents, ester solvents, aromatic hydrocarbon solvents, amide solvents and the like.

Examples of ether solvents include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol-1-monomethyl ether acetate (PGMEA), and 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole And aromatic ethers such as phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole and the like.

Examples of ester solvents include aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, n-butyl benzoate and the like.

Examples of the aromatic hydrocarbon solvent include toluene, xylene, cyclohexylbenzene, 3-isopropylbiphenyl, 1,2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, methylnaphthalene and the like.

Examples of the amide solvents include N, N-dimethylformamide, N, N-dimethylacetamide and the like.

Besides these, dimethyl sulfoxide and the like can also be used.

The formation of the hole injection layer 3 by the wet film formation method usually prepares a composition for forming the hole injection layer, and then forms the layer on the layer corresponding to the lower layer of the hole injection layer 3 (usually, the anode 2). The film is formed by coating and drying. The hole injection layer 3 usually dries the coating film by heating, reduced-pressure drying, or the like after film formation.

(Formation of hole injection layer 3 by vacuum evaporation)
When forming the hole injection layer 3 by a vacuum evaporation method, usually, one or two or more of the constituent materials of the hole injection layer 3 (the above-mentioned hole transportable compound, electron accepting compound, etc.) are vacuumed. Put in a crucible installed in the container (if using two or more types of materials, put each one in a separate crucible), evacuate the vacuum container to about 10 ^-4 Pa with a vacuum pump, and then heat the crucible And (if two or more materials are used, usually each crucible is heated) and evaporated while controlling the evaporation amount of the material in the crucible (when two or more materials are used, they are usually independent of each other) To control the amount of evaporation) to form the hole injection layer 3 on the anode 2 on the substrate placed facing the crucible. When two or more kinds of materials are used, the mixture of them may be put in a crucible, heated and evaporated to form the hole injection layer 3.

The degree of vacuum at the time of deposition is not limited as long as the effects of the present invention are not significantly impaired, but usually 0.1 × 10 ⁻⁶ Torr (0.13 × 10 ⁻⁴ Pa) or more and 9.0 × 10 ⁻⁶ Torr (0.13 × 10 ⁻⁴ Pa). 12.0 × 10 ^-4 Pa) or less. The deposition rate is not limited as long as the effect of the present invention is not significantly impaired, but is usually 0.1 Å / sec or more and 5.0 Å / sec or less. The film forming temperature at the time of vapor deposition is not limited as long as the effects of the present invention are not significantly impaired, but it is preferably performed at 10 ° C. or more and 50 ° C. or less.

Hole Transport Layer 4
The hole transport layer 4 is a layer responsible for transporting holes from the anode 2 side to the light emitting layer 5 side. The hole transport layer 4 is not an essential layer in the organic electroluminescent device of the present invention, but it is preferable to provide this layer in order to strengthen the function of transporting holes from the anode 2 to the light emitting layer 5. When the hole transport layer 4 is provided, the hole transport layer 4 is generally formed between the anode 2 and the light emitting layer 5. When the hole injection layer 3 is present, the hole transport layer 4 is formed between the hole injection layer 3 and the light emitting layer 5.

The film thickness of the hole transport layer 4 is usually 5 nm or more, preferably 10 nm or more, and usually 300 nm or less, preferably 100 nm or less.

The method of forming the hole transport layer 4 may be vacuum evaporation or wet film formation. It is preferable to form by a wet film-forming method at the point which is excellent in film-forming property.

The hole transport layer 4 usually contains a hole transportable compound to be the hole transport layer 4. The hole transporting compound contained in the hole transporting layer 4 is, in particular, a secondary or more tertiary compound represented by 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl. Aromatic diamines containing an amine and having two or more fused aromatic rings substituted by nitrogen atoms (JP-A-5-234681), 4,4 ′, 4 ′ ′-tris (1-naphthylphenylamino) triphenylamine Et al. (J. Lumin., Vol. 72-74, 985, 1997), and aromatic amine compounds composed of tetramer of triphenylamine (Chem. Commun., P. 2175). , 1996), spiro compounds such as 2,2 ', 7,7'-tetrakis- (diphenylamino) -9,9'-spirobifluorene (Synth. Metals, vol. 91) 209 pp., 1997), 4,4'-N, carbazole derivatives such as N'- dicarbazole biphenyl. Polyvinyl carbazole, polyvinyl triphenylamine (Japanese Patent Application Laid-Open No. 7-53953), polyarylene ether sulfone containing tetraphenyl benzidine (Polym. Adv. Tech., Volume 7, page 33, 1996) and the like can also be preferably used. .

(Formation of hole transport layer 4 by wet film formation method)
In the case of forming the hole transport layer 4 by a wet film formation method, in place of the composition for forming a hole injection layer, in the same manner as in the case of forming the hole injection layer 3 described above by a wet film formation method. It forms using the composition for positive hole transport layer formation.

In the case of forming the hole transport layer 4 by a wet film formation method, generally, the composition for forming a hole transport layer further contains a solvent. As the solvent used for the composition for forming a hole transport layer, the same solvent as the solvent used for the composition for forming a hole injection layer described above can be used.

The concentration of the hole transportable compound in the composition for forming a hole transport layer can be in the same range as the concentration of the hole transportable compound in the composition for forming a hole injection layer.

The formation of the hole transport layer 4 by the wet film formation method can be performed in the same manner as the film formation method of the hole injection layer 3 described above.

(Formation of hole transport layer 4 by vacuum evaporation)
Also in the case of forming the hole transport layer 4 by the vacuum evaporation method, holes are usually substituted for the constituent material of the hole injection layer 3 in the same manner as in the case of forming the hole injection layer 3 described above by the vacuum evaporation method. It can be formed using the constituent material of the transport layer 4. The film forming conditions such as the degree of vacuum at the time of vapor deposition, the vapor deposition rate, and the temperature can be formed under the same conditions as the vacuum vapor deposition of the hole injection layer 3.

<Light emitting layer 5>
The light emitting layer 5 is a layer having a function of emitting light by being excited by recombination of holes injected from the anode 2 and electrons injected from the cathode 9 when an electric field is applied between a pair of electrodes. .

The light emitting layer 5 is a layer formed between the anode 2 and the cathode 9. The light emitting layer 5 is formed between the hole injection layer 3 and the cathode 9 when the hole injection layer 3 is present on the anode 2, and is positive when the hole transport layer 4 is present on the anode 2. It is formed between the hole transport layer 4 and the cathode 9.

The film thickness of the light emitting layer 5 is optional as long as the effects of the present invention are not significantly impaired, but a thicker film is preferable in that defects are not easily generated in the film, and a thinner film is preferable in that a low driving voltage is easily achieved. The thickness of the light emitting layer 5 is preferably 3 nm or more, more preferably 5 nm or more, usually 200 nm or less, and further preferably 100 nm or less.

The light emitting layer 5 contains at least a material having a property of light emission (light emitting material), and preferably contains a material having a charge transporting property (charge transporting material). As the light emitting material, any light emitting layer may contain the iridium complex compound of the present invention, and another light emitting material may be used as appropriate. Hereinafter, other light emitting materials other than the iridium complex compound of the present invention will be described in detail.

(Light emitting material)
The light emitting material emits light at a desired emission wavelength, and is not particularly limited as long as the effects of the present invention are not impaired, and known light emitting materials can be applied. The light emitting material may be a fluorescent light emitting material or a phosphorescent light emitting material, but a material having a good light emitting efficiency is preferable, and a phosphorescent light emitting material is preferable from the viewpoint of the internal quantum efficiency.

Examples of the fluorescent material include the following materials.

Examples of the fluorescent material (blue fluorescent material) giving blue emission include naphthalene, perylene, pyrene, anthracene, coumarin, chrysene, p-bis (2-phenylethenyl) benzene and derivatives thereof.

Examples of the fluorescent material (green fluorescent material) that emits green light include quinacridone derivatives, coumarin derivatives, aluminum complexes such as Al (C ₉ H ₆ NO) _3, and the like.

As a fluorescent light emitting material (yellow fluorescent light emitting material) which gives yellow light emission, rubrene, a perimidone derivative, etc. are mentioned, for example.

As a fluorescent light emitting material (red fluorescent light emitting material) giving red light emission, for example, DCM (4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran) based compound, benzopyran derivative, rhodamine derivative And benzothioxanthene derivatives, azabenzothioxanthene and the like.

As the phosphorescent light emitting material, for example, from Group 7 to Group 11 of the long period periodic table (hereinafter referred to as "long period periodic table" in the case of "periodic table" unless otherwise noted). The organic metal complex etc. which contain the metal chosen are mentioned. Preferred examples of the metal selected from Groups 7 to 11 of the periodic table include ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, gold and the like.

The ligand of the organometallic complex is preferably a ligand in which a (hetero) arylpyridine ligand, a (hetero) aryl group such as a (hetero) arylpyrazole ligand, etc. are linked to pyridine, pyrazole, phenanthroline, etc. In particular, phenylpyridine ligands and phenylpyrazole ligands are preferred. Here, (hetero) aryl represents an aryl group or a heteroaryl group.

Specific examples of preferable phosphorescent materials include tris (2-phenylpyridine) iridium, tris (2-phenylpyridine) ruthenium, tris (2-phenylpyridine) palladium, bis (2-phenylpyridine) platinum, tris (2 Phenylpyridine complexes such as -phenylpyridine) osmium and tris (2-phenylpyridine) rhenium; and porphyrin complexes such as octaethyl platinum porphyrin, octaphenyl platinum porphyrin, octaethyl palladium porphyrin and octaphenyl palladium porphyrin.

As a light emitting material of a polymer type, poly (9,9-dioctylfluorene-2,7-diyl), poly [(9,9-dioctylfluorene-2,7-diyl) -co- (4,4'-) (N- (4-sec-butylphenyl)) diphenylamine)], poly [(9,9-dioctylfluorene-2,7-diyl) -co- (1,4-benzo-2 {2,1'-3] And polyphenylene vinylene materials such as poly [2-methoxy-5- (2-ethylhexyloxy) -1,4-phenylene vinylene].

(Charge transportable material)
The charge transportable material is a material having positive charge (hole) or negative charge (electron) transportability, and is not particularly limited as long as the effects of the present invention are not impaired, and known materials can be applied.

As the charge transporting material, compounds conventionally used in the light emitting layer 5 of the organic electroluminescent device can be used, and in particular, compounds used as a host material of the light emitting layer 5 are preferable.

Specific examples of the charge transporting material include aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzylphenyl compounds, and compounds in which tertiary amines are linked by a fluorene group. Other than the compounds exemplified as the hole transport compound of the hole injection layer 3 such as hydrazone compounds, silazane compounds, silanamine compounds, phosphamine compounds, quinacridone compounds etc., anthracene compounds, pyrene compounds And electron transporting compounds such as carbazole compounds, pyridine compounds, phenanthroline compounds, oxadiazole compounds, and silole compounds.

The charge transporting material includes two or more tertiary amines represented by 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl and two or more fused aromatic rings. Aromatic amine compounds having a starburst structure, such as aromatic diamines substituted by nitrogen atoms (JP-A-5-234681), 4,4 ′, 4 ′ ′-tris (1-naphthylphenylamino) triphenylamine, etc. (J. Lumin., 72-74, 985, 1997), aromatic amine compounds composed of tetramer of triphenylamine (Chem. Commun., 2175, 1996), 2, 2 ', Fluorene compounds such as 7,7'-tetrakis- (diphenylamino) -9,9'-spirobifluorene (Synth. Metals, vol. 91, p. 209, 1997) ), 4,4'-N, N'- compounds exemplified as hole-transporting compound of the hole transporting layer 4 of carbazole compounds such as di-biphenyl, or the like can be preferably used. In addition, 2- (4-biphenylyl) -5- (p-tertiary butylphenyl) -1,3,4-oxadiazole (tBu-PBD), 2,5-bis (1-naphthyl) -1,3 Oxadiazole compounds such as 4, 4-oxadiazole (BND), 2, 5-bis (6 '-(2', 2 ''-bipyridyl))-1, 1-dimethyl-3,4-diphenylsilole ( Also included are silole compounds such as PyPySPyPy), phenanthroline compounds such as bathophenanthroline (BPhen) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP, vasocuproin) and the like.

(Formation of light emitting layer 5 by wet film formation method)
Although the formation method of the light emitting layer 5 may be a vacuum deposition method or a wet film formation method, the wet film formation method is preferable because of excellent film formability.

When the light emitting layer 5 is formed by the wet film formation method, light emission is usually performed instead of the composition for forming the hole injection layer in the same manner as in the case where the above-mentioned hole injection layer 3 is formed by the wet film formation method. It forms using the composition for light emitting layer formation prepared by mixing the material used as the layer 5 with the soluble solvent (solvent for light emitting layers). In the present invention, it is preferable to use the iridium complex compound-containing composition of the present invention as the composition for forming a light emitting layer.

As the solvent, for example, ether solvents, ester solvents, aromatic hydrocarbon solvents, amide solvents mentioned for the formation of the hole injection layer 3, alkane solvents, halogenated aromatic carbonized water solvents, fat Group alcohol solvents, alicyclic alcohol solvents, aliphatic ketone solvents, and alicyclic ketone solvents. The solvent to be used is as illustrated also as a solvent of the iridium complex compound containing composition of this invention. Although the specific example of a solvent is given to the following, it will not be limited to these, unless the effect of the present invention is spoiled.

For example, aliphatic ether solvents such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol-1-monomethyl ether acetate (PGMEA); 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2 Aromatic ether solvents such as-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole, diphenyl ether; phenyl acetate, phenyl propionate, methyl benzoate, benzoic acid Aromatic ester solvents such as ethyl, propyl benzoate and n-butyl benzoate; toluene, xylene, mesitylene, cyclohexylbenzene, tetralin, 3-isopropylbiphenyl, 1,2,3,4- Aromatic hydrocarbon solvents such as tramethylbenzene, 1,4-diisopropylbenzene, methylnaphthalene; amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide; n-decane, cyclohexane, ethylcyclohexane, Alkane solvents such as decalin and bicyclohexane; halogenated aromatic hydrocarbon solvents such as chlorobenzene, dichlorobenzene and trichlorobenzene; aliphatic alcohol solvents such as butanol and hexanol; alicyclic alcohols such as cyclohexanol and cyclooctanol Aliphatic ketone solvents such as methyl ethyl ketone and dibutyl ketone; and alicyclic ketone solvents such as cyclohexanone, cyclooctanone and phencone. Among these, alkane solvents and aromatic hydrocarbon solvents are particularly preferable.

In order to obtain a more uniform film, it is preferable that the solvent evaporates at an appropriate rate from the liquid film immediately after film formation. Therefore, as described above, the boiling point of the solvent used is usually 80 ° C. or more, preferably 100 ° C. or more, more preferably 120 ° C. or more, and usually 270 ° C. or less, preferably 250 ° C. or less, more preferably 230 ° C. or less It is.

Although the amount of the solvent used is optional as long as the effects of the present invention are not significantly impaired, the total content in the composition for forming a light emitting layer, that is, the composition containing an iridium complex compound is low in viscosity and thus film forming operation It is preferable that the number is large because it is easy to perform, and it is preferable that the thickness is low and it is easy to form a thick film. As described above, the content of the solvent is preferably 1% by mass or more, more preferably 10% by mass or more, particularly preferably 50% by mass or more, and preferably 99.99% by mass or less in the iridium complex compound-containing composition. More preferably, it is 99.9% by mass or less, particularly preferably 99% by mass or less.

Heating or depressurization can be used as a solvent removal method after wet film formation. As a heating means used in the heating method, a clean oven or a hot plate is preferable because heat is uniformly applied to the entire film.

The heating temperature in the heating step is optional as long as the effects of the present invention are not significantly impaired, but a higher temperature is preferable in terms of shortening the drying time, and a lower temperature is preferable in terms of less damage to the material. The upper limit of the heating temperature is usually 250 ° C. or less, preferably 200 ° C. or less, and more preferably 150 ° C. or less. The lower limit of the heating temperature is usually 30 ° C. or more, preferably 50 ° C. or more, and more preferably 80 ° C. or more. The temperature exceeding the above-mentioned upper limit is higher than the heat resistance of the charge transport material or phosphorescent light emitting material which is usually used, and is not preferable because it may be decomposed or crystallized. If the heating temperature is less than the above lower limit, it takes a long time to remove the solvent, which is not preferable. The heating time in the heating step is appropriately determined by the boiling point and vapor pressure of the solvent in the composition for forming a light emitting layer, the heat resistance of the material, and the heating conditions.

(Formation of light emitting layer 5 by vacuum evaporation method)
When forming the light emitting layer 5 by a vacuum evaporation method, usually, one or two or more kinds of constituent materials of the light emitting layer 5 (the above-mentioned light emitting material, charge transporting compound, etc.) are placed in a vacuum vessel. (Equipment of two or more types of materials, usually put each in separate crucibles), evacuate the inside of the vacuum vessel to about 10 ^-4 Pa with a vacuum pump, then heat the crucible (two or more types of materials When using materials, it is usually evaporated while controlling the evaporation amount of the material in the crucible by heating each crucible) (when using two or more types of materials, the evaporation amount is usually controlled independently of each other) Evaporation) forms the light emitting layer 5 on the hole injection layer 3 or the hole transport layer 4 placed facing the crucible. When two or more types of materials are used, the mixture thereof may be put in a crucible, heated and evaporated to form the light emitting layer 5.

<Hole blocking layer 6>
The hole blocking layer 6 may be provided between the light emitting layer 5 and the electron injection layer 8 described later. The hole blocking layer 6 is a layer stacked on the light emitting layer 5 so as to be in contact with the interface of the light emitting layer 5 on the cathode 9 side.

The hole blocking layer 6 has a role to block the transfer of holes transferred from the anode 2 to the cathode 9 and a role to efficiently transport electrons injected from the cathode 9 toward the light emitting layer 5. Have. The physical properties required for the material constituting the hole blocking layer 6 include high electron mobility and low hole mobility, large energy gap (difference between HOMO and LUMO), excited triplet level (T1) Is high.

As a material of the hole blocking layer 6 which satisfies such conditions, for example, bis (2-methyl-8-quinolinolato) (phenolato) aluminum, bis (2-methyl-8-quinolinolato) (triphenylsilanolato) aluminum Mixed ligand complexes, etc., metal complexes such as bis (2-methyl-8-quinolato) aluminum-μ-oxo-bis- (2-methyl-8-quinolinolato) aluminum binuclear metal complex, distyrylbiphenyl derivatives, etc. Styryl compounds (JP-A-11-242996), triazole derivatives such as 3- (4-biphenylyl) -4-phenyl-5 (4-tert-butylphenyl) -1,2,4-triazole 7-41759), phenanthroline derivatives such as basokuproin (Japanese Patent Laid-Open No. 10-79297), etc. It is below. A compound having at least one pyridine ring substituted with the 2, 4, 6 position described in WO 2005/022962 is also preferable as a material of the hole blocking layer 6.

The formation method of the hole blocking layer 6 is not limited, and can be formed in the same manner as the formation method of the light emitting layer 5 described above.

The thickness of the hole blocking layer 6 is arbitrary as long as the effects of the present invention are not significantly impaired, but is usually 0.3 nm or more, preferably 0.5 nm or more, and usually 100 nm or less, preferably 50 nm or less.

<Electron transport layer 7>
The electron transport layer 7 is provided between the light emitting layer 5 or the hole element layer 6 and the electron injection layer 8 for the purpose of further improving the current efficiency of the element.

The electron transport layer 7 is formed of a compound capable of efficiently transporting electrons injected from the cathode 9 in the direction of the light emitting layer 5 between electrodes to which an electric field is applied. The electron transport compound used for the electron transport layer 7 has high electron injection efficiency from the cathode 9 or the electron injection layer 8 and can transport the injected electrons efficiently with high electron mobility. It is necessary to be a compound.

Examples of the electron transporting compound satisfying such conditions include metal complexes such as aluminum complexes of 8-hydroxyquinoline (JP-A-59-194393), metal complexes of 10-hydroxybenzo [h] quinoline, and oxa Diazole derivatives, distyrylbiphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, trisbenzimidazolylbenzene (US Patent No. 5645948), Quinoxaline compounds (JP-A-6-207169), phenanthroline derivatives (JP-A-5-313459), 2-t-butyl-9,10-N, N'-dicyanoanthraquinone diimine, n-type hydrogenated amorphous Silicon carbide, n-type sulfurization Lead, etc. n-type zinc selenide.

The film thickness of the electron transport layer 7 is usually 1 nm or more, preferably 5 nm or more, and usually 300 nm or less, preferably 100 nm or less.

The electron transport layer 7 is formed by laminating on the light emitting layer 5 or the hole blocking layer 6 by a wet film forming method or a vacuum evaporation method in the same manner as the light emitting layer 5. Usually, a vacuum evaporation method is used.

<Electron injection layer 8>
The electron injection layer 8 plays a role of efficiently injecting electrons injected from the cathode 9 into the electron transport layer 7 or the light emitting layer 5.

For efficient electron injection, the material forming the electron injection layer 8 is preferably a metal having a low work function. As an example, an alkali metal such as sodium or cesium, an alkaline earth metal such as barium or calcium, or the like is used.

The film thickness of the electron injection layer 8 is preferably 0.1 to 5 nm.

Inserting an ultrathin insulating film (film thickness of about 0.1 to 5 nm) of LiF, MgF ₂ , Li ₂ O, Cs ₂ CO ₃ or the like as the electron injection layer 8 at the interface between the cathode 9 and the electron transport layer 7 Is also an effective method to improve the efficiency of the device (Appl. Phys. Lett., 70, 152, 1997; JP 10-74586; IEEE Trans. Electron. Devices, 44, 1245, 1997; SID 04 Digest, page 154).
Furthermore, an alkali metal such as sodium, potassium, cesium, lithium or rubidium is doped to an organic electron transport material represented by a metal complex such as a nitrogen-containing heterocyclic compound such as bathophenanthroline or an aluminum complex of 8-hydroxyquinoline ( The electron injection / transportability is improved by the methods disclosed in JP-A-10-270171, JP-A-2002-100478, JP-A-2002-100482, etc., and it becomes possible to achieve both excellent film quality. preferable. The film thickness in this case is usually 5 nm or more, preferably 10 nm or more, and usually 200 nm or less, preferably 100 nm or less.

The electron injection layer 8 is formed by laminating on the light emitting layer 5 or the hole blocking layer 6 or the electron transport layer 7 thereon by a wet film forming method or a vacuum evaporation method in the same manner as the light emitting layer 5.
The details of the wet film formation method are the same as those of the light emitting layer 5 described above.

<Cathode 9>
The cathode 9 plays a role of injecting electrons into a layer on the light emitting layer 5 side (the electron injection layer 8 or the light emitting layer 5 or the like). As a material of the cathode 9, although it is possible to use the material used for the above-mentioned anode 2, it is preferable to use a metal having a low work function in order to efficiently carry out electron injection, for example, tin, magnesium And metals such as indium, calcium, aluminum and silver, or alloys thereof. Examples of the material of the cathode 9 include low work function alloy electrodes such as magnesium-silver alloy, magnesium-indium alloy, and aluminum-lithium alloy.

From the viewpoint of the stability of the device, it is preferable to deposit a metal layer having a high work function and stable to the atmosphere on the cathode 9 to protect the cathode 9 made of a low work function metal. As a metal to laminate | stack, metals, such as aluminum, silver, copper, nickel, chromium, gold, platinum, are mentioned, for example.

The film thickness of the cathode is usually the same as that of the anode 2.

<Other component layers>
In the above, the element having the layer configuration shown in FIG. 1 has been mainly described, but in the organic electroluminescent element of the present invention, between the anode 2 and the cathode 9 and the light emitting layer 5, unless the performance is impaired, In addition to a certain layer, any layer may be included, and any layer other than the light emitting layer 5 may be omitted.

For example, it is also effective to provide an electron blocking layer between the hole transport layer 4 and the light emitting layer 5 for the same purpose as the hole blocking layer 8. The electron blocking layer prevents the electrons moving from the light emitting layer 5 from reaching the hole transporting layer 4, thereby increasing the probability of recombination with holes in the light emitting layer 5, thereby generating the generated excitons. It has a role of being confined in the light emitting layer 5 and a role of efficiently transporting holes injected from the hole transport layer 4 in the direction of the light emitting layer 5.

The characteristics required for the electron blocking layer include high hole transportability, large energy gap (difference between HOMO and LUMO), and high excited triplet level (T1).

In the case where the light emitting layer 5 is formed by a wet film formation method, it is preferable to also form the electron blocking layer by a wet film formation method because this facilitates the element production.
For this reason, it is preferable that the electron blocking layer also have wet film forming compatibility, and as a material used for such an electron blocking layer, a copolymer of dioctyl fluorene and triphenylamine represented by F8-TFB (International Publication No. 2004/084260) and the like can be mentioned.

The structure reverse to that of FIG. 1, that is, on the substrate 1, the cathode 9, the electron injection layer 8, the electron transport layer 7, the hole blocking layer 6, the light emitting layer 5, the hole transport layer 4, the hole injection layer 3, the anode It is also possible to stack in the order of two. It is also possible to provide the organic electroluminescent device of the present invention between two substrates of which at least one is highly transparent.

It is also possible to adopt a structure in which a plurality of layers are stacked (the structure in which a plurality of light emitting units are stacked) shown in FIG. In that case, if, for example, V ₂ O ₅ or the like is used as the charge generation layer instead of the interface layer between the steps (between the light emitting units) (the anode is ITO and the two layers if the cathode is Al), the barrier between the steps Is more preferable from the viewpoint of light emission efficiency and drive voltage.

The present invention can be applied to any of organic electroluminescent devices, devices having a structure in which the organic electroluminescent devices are arranged in an array, and structures in which an anode and a cathode are arranged in an XY matrix.

[Display device and lighting device]
The display device and the illumination device of the present invention use the organic electroluminescent device of the present invention as described above. There are no particular restrictions on the type and structure of the display device and the lighting device of the present invention, and the display can be assembled according to a conventional method using the organic electroluminescent device of the present invention.

For example, the display device and the lighting device according to the present invention can be described in the manner described in "Organic EL display" (Am Co., published on August 20, 2004, Toshitoshi Shitashi, Adachi Senya, Murata Hideyuki). Can be formed.

Hereinafter, the present invention will be more specifically described with reference to examples. The present invention is not limited to the following examples, and the present invention can be implemented with various modifications without departing from the scope of the invention.
In the following synthesis examples, all reactions were carried out under a nitrogen stream.

[Synthesis of Iridium Complex Compound]
Synthesis Example 1: Synthesis of Compound 1

In a 200 mL flask, 5.0 g of 9,9-dimethylfluorene-2-carboxylic acid, 100 mL of dry dichloromethane, 3.3 g of thionyl chloride, and 100 μL of N, N-dimethylformamide are added in this order at room temperature. Stir for 5 hours. The solvent was removed under reduced pressure, 5 ml of dry tetrahydrofuran was added to the residue, and further, a solution of 2-amino-3-chlorobenzonitrile: 2.7 g of dry pyridine: 10 ml was added and stirred at room temperature. After 10 minutes, an additional 0.7 g of 2-amino-3-chlorobenzonitrile was added, and the mixture was stirred at room temperature for a total of 3 hours. The solvent was removed under reduced pressure, and the solution was separated and washed with 300 mL of toluene and 130 mL of 1 N hydrochloric acid, dried over magnesium sulfate, filtered and dried under reduced pressure. Intermediate 1 was obtained as 8.8 g of yellow solid. Intermediate 1 was subjected to the next reaction without purification.

In a 1 L eggplant flask, 27.5 g of 2,6-dibromo-m-xylene, 30.3 g of 3- (6-phenyl-n-hexyl) phenylboronic acid, tetrakis (triphenylphosphine) palladium (0): 2 .5 g, 2 M aqueous solution of tripotassium phosphate: 2500 mL, toluene: 300 mL and ethanol: 100 mL were added, and the mixture was stirred under reflux in an oil bath at 100 ° C. for 3 hours.

After cooling to room temperature, the aqueous phase was removed and the solvent removed in vacuo. The residue was purified by silica gel column chromatography (neutral gel 650 mL, hexane only) to obtain 39.4 g of Intermediate 2 as a colorless oil.

A 200 mL flask was charged with 2.2 g of sharp magnesium and stirred for 1 hour under reduced pressure. Thereafter, a solution of 37.8 g of Intermediate 2: 3 in dry tetrahydrofuran: 45 mL was added dropwise over 30 minutes at room temperature. Then, it stirred at room temperature for further 1 hour. The reaction mixture was added dropwise at room temperature to a solution of 8.8 g of Intermediate 1: 8 in dry tetrahydrofuran: 35 mL, and the mixture was stirred at 85 ° C. for 3 hours. Then, after adding 10 mL of saturated aqueous ammonium chloride solution, the solvent was removed under reduced pressure, and the residue was purified by silica gel column chromatography (Acid gel 500 mL, hexane → hexane / ethyl acetate 8/2), and intermediate 3 was removed 11.1 g was obtained (however, the dehydrobrominated intermediate 2 was mixed, and 13.3 g in total. The next reaction was not affected, so the mixture was subjected to the next reaction). .

Intermediate 3: Net 11.1 g, 2-naphthaleneboronic acid: 5.4 g, palladium acetate: 183 mg, S-Phos (2-dicyclohexylphosphino-2 ', 6'-dimethoxybiphenyl): 656 mg in a 1 L eggplant flask Tripotassium phosphate: 6.6 g and dehydrated deoxygenated toluene: 100 mL were added, and the mixture was stirred in a 130 ° C. oil bath. On the way, after 3 hours, add sodium hydroxide: 2.0 g, ethanol: 25 mL and water: 25 mL, and after 4 hours, add potassium hydroxide: 2.7 g, palladium acetate: 100 mg, S-Phos: 400 mg and tetrahydrofuran: 10 mL After 5 hours, add barium hydroxide octahydrate: 3.0 g, palladium acetate: 100 mg, S-Phos: 400 mg and tetrahydrofuran: 10 mL, and after 6 hours, 2-naphthaleneboronic acid: 2.3 g, palladium acetate: 100 mg S-Phos: 400 mg and tetrahydrofuran: 10 mL were added, and after 6.5 hours, potassium hydroxide: 1.2 g, ethanol: 50 mL and water: 50 mL were added and reacted for a total of 11 hours, but the conversion was low.

The next day, 1.2 g of tetrakistriphenylphosphine palladium (0) was added, and stirring was resumed at 120 ° C. After 1 hour, add N, N-dimethylformamide: 100 mL and after 2.5 hours, 2-naphthaleneboronic acid: 3.1 g, palladium acetate: 100 mg, S-Phos: 400 mg and N, N-dimethylformamide: 15 mL In addition, after 3.5 hours, 100 mg of palladium acetate, 400 mg of S-Phos and 15 mL of N, N-dimethylformamide were added and reacted for a total of 8 hours, and the raw materials disappeared. Thereafter, the solvent is removed under reduced pressure, and the obtained residue is purified by silica gel column chromatography (neutral gel 700 mL, dichloromethane / hexane = 2/8 to 1/1) to obtain 11.0 g of intermediate 4 as an orange solid Obtained.

In a 1-L eggplant flask, 31.7 g of 2- (3-bromophenyl) benzothiazole, 33.7 g of B- [1,1 ': 3', 1 ''-terphenyl] -3-ylboronic acid, tetrakis ( Triphenylphosphine) palladium (0): 2.2 g was added, and further nitrogen-bubbled toluene: 350 mL, ethanol: 100 mL and 2 M aqueous solution of tripotassium phosphate: 200 mL were added and stirred at 100 ° C. for 4 hours. After cooling to room temperature, the aqueous phase is removed, the solvent is removed, and the residue thus obtained is purified by silica gel column chromatography (gel 600 mL, dichloromethane / hexane = 3/7 → 5/5), and Intermediate 5 is 45 I got .9g.

Intermediate 5: 28.9 g, iridium chloride n hydrate (made of Furuya metal, 52% iridium content): 10.7 g of 2-ethoxyethanol: 0.7 L and water: 60 mL are added to a 1 L eggplant flask, Stir at reflux for 9 hours. The precipitate is filtered and half of the cake obtained is placed in a 500 mL eggplant flask, and 3,4-heptanedione: 7.4 g, potassium carbonate: 10.2 g and 2-ethoxyethanol: 250 mL are added and refluxed for 8 hours It stirred. After cooling to room temperature, the solvent of the filtered solution was removed under reduced pressure, and the obtained residue was purified by silica gel column chromatography (gel 500 mL, developed with dichloromethane) to obtain 14.9 g of Intermediate 6.

In a 100 mL recovery flask, Intermediate 4: 10.8 g, Intermediate 6: 4.2 g, Silver trifluoromethanesulfonate: 1.5 g and toluene: 7.5 mL were added, and the mixture was stirred in an oil bath at 225 ° C. for 2 hours. During the reaction, nitrogen was flowed to a three-way cock connected directly to 100 mL eggplant to remove volatilized toluene. After cooling to room temperature, the obtained solid was flowed through silica gel column chromatography (neutral gel 400 mL, toluene / hexane = 35/65 to 1/1, and then the target substance was allowed to flow down with dichloromethane / hexane = 1/1. ) To give 0.96 g of Compound 1 as a red solid.

Synthesis Example 2: Synthesis of Compound 2

In a 1-liter eggplant flask, 4.9 g of 9,9-dimethylfluorene-2-carboxylic acid, 100 mL of dry dichloromethane, 2 mL of thionyl chloride, and 100 μL of N, N-dimethylformamide are added in this order and stirred at room temperature for 2 hours did. The solvent was removed under reduced pressure, 50 mL of dry N-methylpyrrolidone was added to the residue, and a 50 mL solution of 2.6 g of dry N-methylpyrrolidone was further added, followed by stirring at room temperature for 2 hours. The reaction solution was poured into 800 mL of water, neutralized with 2 M aqueous solution of tripotassium phosphate: 100 mL, filtered, washed with water and dried under reduced pressure to obtain Intermediate 7 as a cream solid of 6.2 g.

In a 1-liter eggplant flask, 6.2 g of intermediate 7, iridium chloride n hydrate (made of Furuya metal, iridium content 52%): 3.2 g, 50 mL of 2-ethoxyethanol and 10 mL of water are added, and it is for 6 hours Stir at reflux. A cake obtained by filtering the deposit: 5.0 g of 9.1 g is put into a 1 L eggplant flask, 3,5-heptanedione: 2.6 g, potassium carbonate: 8.0 g and 2-ethoxyethanol: 200 mL Was added and stirred at reflux for 1 hour 45 minutes. After cooling to room temperature, the solvent is removed under reduced pressure, and the obtained residue is separated and washed with dichloromethane: 300 mL and water: 300 mL, and then the solvent of the oil phase is removed and the residue obtained is silica gel column chromatography (gel 500 mL The residue was purified with dichloromethane / hexane = 8/2 to give 2.0 g of Intermediate 8.

Intermediate 8: 1.4 g, Intermediate 4: 4.3 g, and silver trifluoromethanesulfonate: 0.57 g were added to a 100 mL recovery flask, and the mixture was stirred in an oil bath at 220 ° C. for 2 hours. After cooling to room temperature, the obtained solid was subjected to silica gel column chromatography (neutral gel 400 mL, toluene / hexane = 4/6 to 1/1, and then the target substance was allowed to flow down with dichloromethane / hexane = 1/1. ) To give 0.8 g of Compound 2 as a red solid.

[Comparison of solvent solubility]
Example 1
Compound 1 was mixed with cyclohexylbenzene so as to be 3% by mass. Solubility was observed with only manual shaking for 2 minutes at room temperature. Then, after heating for 5 minutes with a 100 degreeC hot plate, it left still at room temperature for 40 hours, and observed the presence or absence of precipitation, etc., respectively.

Example 2, Comparative Examples 1 and 2
The same procedure as in Example 1 was repeated except that Compound 1 was replaced with Compound 2, Compound D-1 below, or Compound D-2 below. Compound D-1 was synthesized based on WO 2015/087961, and Compound D-2 was synthesized based on WO 2014/024889.

The above results are summarized in Table 1.
It can be seen from Table 1 that the iridium complex compound of the present invention is excellent in both the solubility upon dissolution and the dissolution stability after a lapse of time after dissolution.

[Measurement of maximum emission wavelength and half width]
Example 3
Compound 1 was dissolved in 2-methyltetrahydrofuran (manufactured by Aldrich, dehydrated, with no stabilizer added) at room temperature to prepare a 1 × 10 ⁻⁵ mol / L solution. This solution was put into a quartz cell equipped with a Teflon (registered trademark) cock, nitrogen bubbling was performed for 20 minutes or more, and then a phosphorescence spectrum was measured at room temperature. The wavelength showing the maximum value of the obtained phosphorescence spectrum intensity was taken as the maximum emission wavelength. Further, the width of the spectral intensity half of the maximum emission wavelength was taken as the half width.

The following equipment was used for the measurement of the emission spectrum.
Device: Hamamatsu Photonics Co., Ltd. Organic EL quantum yield measurement device C9920-02
Light source: monochrome light source L9799-01
Detector: Multi-channel detector PMA-11
Excitation light: 380 nm

Example 4, Comparative Examples 3 and 4
The same procedure as in Example 3 was repeated, except that Compound 2, Compound D-1 or Compound D-2 was used instead of Compound 1.

The results are shown in Table 2 and FIG.

In Example 3 and Example 4, the half width at the maximum emission wavelength of Example 3 and Example 4 indicated by the line connecting the data of Comparative Example 3 and Comparative Example 4 in FIG. showed that. From these results, it can be said that the iridium complex compound of the present invention exhibits a wide half width which deviates from the linear relationship between the maximum emission wavelength and the half width of Comparative Example 3 and Comparative Example 4.

[Synthesis of Iridium Complex Compound]
Synthesis Example 3: Synthesis of Compound 3

(Reaction 1)
In a 1 L eggplant flask, 3-bromo-4-hydroxybenzoic acid (50 g), methanol (400 mL) and sulfuric acid (23 mL) were added, and the mixture was stirred under reflux in an oil bath at 95 ° C. for 3 hours. Thereafter, sodium carbonate (60 g) and water (200 mL) were added to make basic, and then extracted with dichloromethane (250 mL) six times. The aqueous phase was added with 35% hydrochloric acid (15 mL) and extracted five times with dichloromethane (250 mL). The oil phase was dried over magnesium sulfate (50 mL) and filtered, and the solvent was removed under reduced pressure to obtain 53.6 g of methyl ester.

(Reaction 2)
2-methylphenylboronic acid (16.5 g), palladium acetate (0.50 g), S-Phos (2-dicyclohexylphosphino-2 ', 6-dimethoxybiphenyl) in the methyl ester form (27.7 g) of Reaction 1 ) (1.9 g), tripotassium phosphate (46.3 g) and deoxygenated toluene (500 mL) were added and stirred at 100 ° C. for 5 hours. Then, 35% hydrochloric acid (40 mL), water (160 mL) and dichloromethane (100 mL) were added to recover the oil phase, dissolved in hot ethanol (100 mL), and then water (250 mL) was added to make a powder.
The residue was purified by silica gel column chromatography (neutral gel 200 mL, dichloromethane / hexane = 3/7 to 1/0) to obtain 23.1 g of intermediate 9.

(Reaction 3)
Intermediate 9 (23.1 g), dichloromethane (350 mL), trifluoromethanesulfonic anhydride (35 mL) and triethylamine (30 mL) were added to a 1 L eggplant flask, and stirred at room temperature for 1 hour. Thereafter, water (200 mL) and sodium carbonate (30 g) were added to neutralize, and then the oil phase was dried over magnesium sulfate, filtered and the solvent was removed under reduced pressure.
The resulting residue was purified by silica gel column chromatography (1 cm of neutral gel was loaded on a cone of 9 cm in diameter and eluted with dichloromethane / hexane = 1/1) to obtain 38.3 g of intermediate 10 .

(Reaction 4)
Into a 1 L eggplant flask, add intermediate 10 (15.5 g), palladium acetate (0.94 g), S-Phos (3.6 g), tripotassium phosphate (17.9 g) and dehydrated tetrahydrofuran (300 mL), and add 100 Stir in oil bath for 5 hours. The reaction solution is cooled and filtered, and the solvent is removed under reduced pressure, and the residue thus obtained is purified by silica gel column chromatography (neutral gel 500 mL, dichloromethane / hexane = 2/8 to 3/7) to obtain intermediate 11 I got .7g.

(Reaction 5)
Intermediate 3 (6.7 g), n-hexyl iodide (15.6 g), tetrabutylammonium bromide (1.9 g), and dimethyl sulfoxide (40 mL) were placed in a 1 L eggplant flask, and sodium hydroxide (7. A solution of 0 g) in water (10 mL) was added dropwise and stirred at room temperature for 2.5 hours. Then, a solution of sodium hydroxide (2.0 g) in water (15 mL) was added dropwise and stirred for an additional 1.5 hours. Thereafter, an aqueous solution of 35% hydrochloric acid (50 mL) and water (150 mL) is added, extracted with ethyl acetate (200 mL), dried over magnesium sulfate, filtered, and silica gel column chromatography (neutral gel 200 mL, ethyl acetate / hexane = The residue was purified by 1/9 to 3/7) to obtain 9.9 g of Intermediate 12.

(Reaction 6)
In a 1-L separable flask, 2-aminobenzonitrile (23.4 g) and acetic acid (500 mL) were added, and bromine (30 mL) was added dropwise over 20 minutes at room temperature. In another 1 L separable flask, 2-aminobenzonitrile (50.4 g) and acetic acid (1 L) were added, and bromine (65 mL) was added dropwise over 20 minutes. After reacting for 5 hours at room temperature, water (50 mL) was added and filtered.
The filtrate was combined, suspension washed with water (500 mL) and dried under reduced pressure while heating to give 2-amino-3,5-dibromobenzonitrile (141.8 g).

(Reaction 7)
In a 1 L eggplant flask, 2-amino-3,5-dibromobenzonitrile (28.9 g), 2-naphthaleneboronic acid (37.7 g), tetrakis (triphenylphosphine) palladium (5.2 g), 2 M phosphoric acid Potassium (300 mL), toluene (300 mL) and ethanol (100 mL) were added, and the mixture was stirred in a 105 ° C. oil bath for 4.5 hours. During the addition, 2-naphthylboronic acid (12.5 g) was additionally charged. Thereafter, the aqueous phase is removed at room temperature, the solvent is removed under reduced pressure, and the residue thus obtained is purified by silica gel column chromatography (neutral gel 650 mL, dichloromethane / hexane = 65/35 to 6/4), and an intermediate is obtained Obtained 37.1 g of 13.

(Reaction 8)
Intermediate 12 (9.9 g), dry dichloromethane (100 mL), thionyl chloride (2.4 mL) and N, N-dimethylformamide (100 μL) were placed in a 1 L eggplant flask, and stirred at room temperature for 1.5 hours. Thereafter, the solvent was removed to obtain an acid chloride.
Intermediate 13 (10.2 g) and dehydrated pyridine (40 mL) were placed in another 1 L eggplant flask, and a solution of the acid chloride in tetrahydrofuran (8 mL) prepared above was added dropwise thereto, and stirred at room temperature for 4 hours. Thereafter, dichloromethane (200 mL) was added and the mixture was washed three times with 1N hydrochloric acid (120 mL), the oil phase was dried over magnesium sulfate and filtered, and the solvent was removed under reduced pressure to obtain 20.1 g of Intermediate 14.

(Reaction 9)
In a 100 mL flask, charged magnesium (5.0 g) was added and stirred for 1 hour under reduced pressure. Thereafter, a solution of 35.0 g of 2-bromo-m-xylene in dry tetrahydrofuran (50 mL) was added dropwise over 30 minutes at room temperature. Then, it stirred at room temperature for further 1 hour. The reaction mixture was added dropwise to a solution of Intermediate 14 (18.9 g) in dry tetrahydrofuran (100 mL) at room temperature, and stirred at 85 ° C. for 2 hours. Then, after adding saturated aqueous ammonium chloride solution (100 mL), extraction is performed with dichloromethane (200 mL), the solvent of the organic phase is removed under reduced pressure, and the residue is silica gel column chromatography (Acid gel 500 mL, hexane / dichloromethane = 6/4) The residue was purified by silica gel column chromatography to obtain 11.5 g of Intermediate 15.

(Reaction 10)

In a 1 L eggplant flask, 2- (3-bromophenyl) benzothiazole (31.7 g), B- [1,1 ': 3', 1 ''-terphenyl] -3-ylboronic acid (33.7 g), Add tetrakis (triphenylphosphine) palladium (0) (2.2 g), add nitrogen-bubbled toluene (350 mL), ethanol (100 mL) and 2M aqueous solution of tripotassium phosphate (200 mL), and stir at 100 ° C for 4 hours did. After cooling to room temperature, the aqueous phase is removed, the solvent is removed, and the residue thus obtained is purified by silica gel column chromatography (gel 600 mL, dichloromethane / hexane = 3/7 → 5/5), and intermediate 16 is 45 I got .9g.

(Reaction 11)

Intermediate 16 (28.9 g), iridium chloride n-hydrate (furuya metal, 52% iridium content) (10.7 g), 2-ethoxyethanol (0.7 L) and water (60 mL) in a 1 L eggplant flask ) Was added and stirred at reflux for 9 hours. The precipitate is filtered and half of the cake obtained is placed in a 500 mL eggplant flask and 3,5-heptanedione (7.4 g), potassium carbonate (10.2 g) and 2-ethoxyethanol (250 mL) are added. Stir at reflux for 8 hours. After cooling to room temperature, the solvent of the filtered solution was removed under reduced pressure, and the obtained residue was purified by silica gel column chromatography (gel 500 mL, developed with dichloromethane) to obtain 14.9 g of Intermediate 17.

(Reaction 12)

Intermediate 15 (11.5 g) and Intermediate 17 (4.2 g) were placed in a 100 mL eggplant-shaped flask, charged in an oil bath, and the temperature was raised from room temperature to 220.degree. When the bath temperature exceeded 210 ° C., silver trifluoromethanesulfonate (1.5 g) was added, and the mixture was stirred for 3 hours. Intermediate 2 (1.0 g) was added after 2 hours on the way. The solid obtained after the reaction was purified by silica gel column chromatography (gel neutral 600 mL, dichloromethane / hexane = 3/7) to obtain 0.8 g of compound 3.

[Confirmation of solvent solubility and dissolution stability after dissolution]
Compound 3 was mixed with cyclohexylbenzene to 3% by mass. When the solubility was observed only by hand shaking at room temperature, all dissolved rapidly. Then, the solution was heated for 5 minutes on a hot plate at 100 ° C., allowed to stand at room temperature for 50 hours, and observed for the presence or absence of precipitation.

[Example 5]
The emission quantum yield and the maximum emission wavelength of Compound 3, which is the iridium complex compound of the present invention, were measured by the following method. The results are shown in Table 3.

<Evaluation of luminescence quantum yield>
Compound 3 was dissolved in 2-methyltetrahydrofuran (manufactured by Aldrich, dehydrated, with no stabilizer added) at room temperature to prepare a 1 × 10 ⁻⁵ mol / l solution. This solution is put into a quartz cell with a Teflon (registered trademark) cock, nitrogen bubbling is performed for 20 minutes or more, an absolute quantum yield is measured at room temperature, and the relative value is set to 1.00 of Comparative Example 5 described below. Calculated.

The following equipment was used for measurement of light emission quantum yield.
Device: Hamamatsu Photonics Co., Ltd. Organic EL quantum yield measurement device C9920-02
Light source: monochrome light source L9799-01
Detector: Multi-channel detector PMA-11
Excitation light: 380 nm

<Measurement of maximum emission wavelength>
A solution of compound 3 dissolved in 2-methyltetrahydrofuran at a concentration of 1 × 10 ^-5 mol / L at normal temperature and phosphorescent with a spectrophotometer (Hamamatsu Photonics Co., Ltd., organic EL quantum yield measurement device C9920-02) The spectrum was measured. The wavelength showing the maximum value of the obtained phosphorescence spectrum intensity was taken as the maximum emission wavelength.

[Comparative Examples 5 to 7]
A solution is prepared in the same manner as in Example 5 except that the compound D-3, the compound D-4, or the compound D-5 shown below is used instead of the compound 3 to measure an emission quantum yield and a maximum emission wavelength. did. The light emission quantum yield was shown by the relative value which set the value of the comparative example 5 to 1.00. Compounds D-3 to D-5 were synthesized based on the description of WO 2015/087961. The results are shown in Table 3.

FIG. 3 shows the relationship between the maximum emission wavelength and the emission quantum yield in Example 5 and Comparative Examples 5 to 7.
With regard to iridium complex compounds that are chemically similar structures, it is known that the emission wavelength and quantum yield often show a linear relationship, particularly in the red emission region (for example, S. Okada, et al, Dalton Trans., 2005, 1583-1590). Comparative Examples 5 to 7 are iridium complex compounds in which a phenyl-quinazoline type ligand and a phenyl-benzothiazole type ligand are combined, and it is considered that there is a similar relationship among them.
The iridium complex compound of the present invention of Example 5 exhibited a quantum yield higher than the emission quantum efficiency at the maximum emission wavelength of Example 5 (compound 3) indicated by the line connecting the data of Comparative Examples 5 to 7.

Although the invention has been described in detail with particular embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention.
This application is based on Japanese patent application 2017-214771 filed on November 7, 2017 and Japanese patent application 2017-214772 filed on November 7, 2017, which is incorporated by reference in its entirety. .

Reference Signs List 1 substrate 2 anode 3 hole injection layer 4 hole transport layer 5 light emitting layer 6 hole blocking layer 7 electron transport layer 8 electron injection layer 9 cathode 10 organic electroluminescent element

Claims

The iridium complex compound represented by following formula (1).

[In formula (1), Ir represents an iridium atom,
C 1 to C 6 represent carbon atoms, and N 1 and N 2 represent nitrogen atoms.
R 1 to R 4 each independently represent a hydrogen atom or a substituent,
and a, b, c and d respectively represent the maximum number of integers that can be substituted on the rings Cy 1 , Cy 2 , Cy 3 and Cy 4 ,
m and n represent 1 or 2, and m + n is 3.
The ring Cy 1 is a fluorene structure represented by the following formula (2) or (2 ′),

When the ring Cy 1 is represented by the formula (2), the ring Cy 2 is a quinoline or naphthyridine structure represented by any one of the following formulas (3) to (5):
When the ring Cy 1 is represented by the formula ( 2 ′ ), the ring Cy 2 is a naphthyridine structure represented by any one of the following formulas (3) to (5):

X 1 to X 18 in formulas (3) to (5) each independently represent a carbon atom or a nitrogen atom,
Ring Cy 3 represents an aromatic ring or heteroaromatic ring containing carbon atoms C 4 and C 5 ,
The ring Cy 4 represents a heteroaromatic ring containing carbon atom C 6 and nitrogen atom N 2 . ]
The iridium complex compound according to claim 1, wherein the ring Cy 4 is a structure represented by the following formula (6).

[In formula (6),
And each of X 19 to X 22 independently represents a carbon atom or a nitrogen atom,
Y represents N (-R 5 ), an oxygen atom or a sulfur atom, and R 5 represents a hydrogen atom or a substituent. ]
The iridium complex compound according to claim 1 or 2, wherein the ring Cy 1 is a fluorene structure represented by the formula (2), and the ring Cy 3 is one represented by the following formula (8).
The iridium complex compound according to any one of claims 1 to 3, wherein Y in the formula (6) is a sulfur atom.
The iridium complex compound according to any one of claims 1 to 4, wherein the number of nitrogen atoms constituting the ring Cy 2 is 2.
A composition comprising the iridium complex compound according to any one of claims 1 to 5 and a solvent.
An organic electroluminescent device comprising the iridium complex compound according to any one of claims 1 to 5.
A display comprising the organic electroluminescent device according to claim 7.
A lighting device comprising the organic electroluminescent device according to claim 7.
The iridium complex compound represented by following formula (7).

[In Formula (7), Ir represents an iridium atom.
C 7 to C 9 represent carbon atoms, and N 3 and N 4 represent nitrogen atoms.
Ring Cy 5 represents an aromatic ring or heteroaromatic ring containing carbon atoms C 7 and C 8 ,
Ring Cy 6 represents a heteroaromatic ring containing carbon atom C 9 and nitrogen atom N 3 ,
X 23 to X 26 each independently represent a carbon atom which may have a substituent, or a nitrogen atom,
Y 2 represents an oxygen atom, a sulfur atom or a selenium atom,
Each of R 10 to R 12 independently represents a hydrogen atom or a substituent.
a ′ and b ′ represent the maximum number of integers that can be substituted on the rings Cy 5 and Cy 6 respectively, and c ′ is 8.
m 'and n' represent 1 or 2, and m '+ n' is 3. ]